Chapter 12

LAMARCK THE ZOÖLOGIST

Although there has been and still may be a difference of opinion as to the value and permanency of Lamarck's theoretical views, there has never been any lack of appreciation of his labors as a systematic zoölogist. He was undoubtedly the greatest zoölogist of his time. Lamarck is the one dominant personage who in the domain of zoölogy filled the interval between Linné and Cuvier, and in acuteness and sound judgment he at times surpassed Cuvier. His was the master mind of the period of systematic zoölogy, which began with Linné--the period which, in the history of zoölogy, preceded that of comparative anatomy and morphology.

After Aristotle, no epoch-making zoölogist arose until Linné was born. In England Linné was preceded by Ray, but binomial nomenclature and the first genuine attempt at the classification of animals dates back to the _Systema Naturæ_ of Linné, the tenth edition of which appeared in 1758.

The contemporaries of Lamarck in biological science, in the eighteenth century, were Camper (1722-89), Spallanzani (1729-99), Wolff (1733-94), Hunter (1728-93), Bichat (1771-1802), and Vicq d'Azyr (1748-94). These were all anatomists and physiologists, the last-named being the first to propose and use the term "comparative anatomy," while Bichat was the founder of histology and pathological anatomy. There was in fact no prominent systematic zoölogist in the interval between Linné and Lamarck. In France there were only two zoölogists of prominence when Lamarck assumed his duties at the Museum. These were Bruguière the conchologist and Olivier the entomologist. In Germany Hermann was the leading systematic zoölogist. We would not forget the labors of the great German anatomist and physiologist Blumenbach, who was also the founder of anthropology; nor the German anatomists Tiedemann, Bojanus, and Carus; nor the embryologist Döllinger. But Lamarck's method and point of view were of a new order--he was much more than a mere systematist. His work in systematic zoölogy, unlike that of Linné, and especially of Cuvier, was that of a far higher grade. Lamarck, besides his rigid, analytical, thorough, and comprehensive work on the invertebrates, whereby he evolved order and system out of the chaotic mass of forms comprised in the Insects and Vermes of Linné, was animated with conceptions and theories to which his forerunners and contemporaries, Geoffroy St. Hilaire excepted, were entire strangers. His tabular view of the classes of the animal kingdom was to his mind a genealogical tree; his idea of the animal kingdom anticipated and was akin to that of our day. He compares the animal series to a tree with its numerous branches, rather than to a single chain of being. This series, as he expressly states, began with the monad and ended with man; it began with the simple and ended with the complex, or, as we should now say, it proceeded from the generalized or undifferentiated to the specialized and differentiated. He perceived that many forms had been subjected to what he calls degeneration, or, as we say, modification, and that the progress from the simple to the complex was by no means direct. Moreover, fossil animals were, according to his views, practically extinct species, and stood in the light of being the ancestors of the members of our existing fauna. In fact, his views, notwithstanding shortcomings and errors in classification naturally due to the limited knowledge of anatomy and development of his time, have been at the end of a century entirely confirmed--a striking testimony to his profound insight, sound judgment, and philosophic breadth.

The reforms that he brought about in the classification of the invertebrate animals were direct and positive improvements, were adopted by Cuvier in his _Règne animal_, and have never been set aside. We owe to him the foundation and definition of the classes of Infusoria, Annelida, Arachnida, and Crustacea, the two latter groups being separated from the insects. He also showed the distinctness of echinoderms from polyps, thus anticipating Leuckart, who established the phylum of Coelenterata nearly half a century later. His special work was the classification of the great group of Mollusca, which he regarded as a class. When in our boyhood days we attempted to arrange our shells, we were taught to use the Lamarckian system, that of Linné having been discarded many years previous. The great reforms in the classification of shells are evidenced by the numerous manuals of conchology based on the works of Lamarck.

We used to hear much of the Lamarckian genera of shells, and Lamarck was the first to perceive the necessity of breaking up into smaller categories the few genera of Linné, which now are regarded as families. He may be said to have had a wonderfully good eye for genera. All his generic divisions were at once accepted, since they were based on valid characters.

Though not a comparative anatomist, he at once perceived the value of a knowledge of the internal structure of animals, and made effective use of the discoveries of Cuvier and of his predecessors--in fact, basing his system of classification on the organs of respiration, circulation, and the nervous system.

He intimated that specific characters vary most, and that the peripheral parts of the body, as the shell, outer protective structures, the limbs, mouth-parts, antennæ, etc., are first affected by the causes which produce variation, while he distinctly states that it requires a longer time for variations to take place in the internal organs. On the latter he relied in defining his classes.

One is curious to know how Lamarck viewed the question of species. This is discussed at length by him in his general essays, which are reproduced farther on in this biography, but his definition of what a species is far surpasses in breadth and terseness, and better satisfies the views now prevailing, than that of any other author.

His definition of a species is as follows:

"Every collection of similar individuals, perpetuated by generation in the same condition, so long as the circumstances of their situation do not change enough to produce variations in their habits, character, and form."

Lamarck's rare skill, thoroughness, and acuteness as an observer, combined with great breadth of view, were also supplemented by the advantages arising from residence in Paris, and his connection with the Museum of Natural History. Paris was in the opening years of the nineteenth century the chief centre of biological science. France having convalesced from the intestinal disorders of the Revolution, and, as the result of her foreign wars, adding to her territory and power, had begun with the strength of a young giant to send out those splendid exploring expeditions which gathered in collections in natural history from all parts of the known or accessible world, and poured them, as it were, into the laps of the professors of the Jardin des Plantes. The shelves and cases of the galleries fairly groaned with the weight of the zoölogical riches which crowded them. From the year 1800 to 1832 the French government showed the greatest activity in sending out exploring expeditions to Egypt, Africa, and the tropics.[119]

The zoölogists who explored Egypt were Geoffroy St. Hilaire and Savigny. Those who visited the East, the South Seas, the East Indian archipelago, and other regions were Bruguière, Olivier, Bory de St. Vincent, Péron, Lesueur, Quoy, Gaimard, Le Vaillant, Edoux, and Souleyet. The natural result was the enormous collections of the Jardin des Plantes, and consequently enlarged views regarding the number and distribution of species, and their relation to their environment.

In Paris, about the time of Lamarck's death, flourished also Savigny, who published his immortal works on the morphology of arthropods and of ascidians; and Straus-Durckheim, whose splendidly illustrated volumes on the anatomy of the cockchafer and of the cat will never cease to be of value; and É. Geoffroy St. Hilaire, whose elaborate and classical works on vertebrate morphology, embryology, and comparative anatomy added so much to the prestige of French science.

We may be sure that Lamarck did his own work without help from others, and gave full credit to those who, like Defrance or Bruguière, aided or immediately preceded him. He probably was lacking in executive force, or in the art which Cuvier knew so well to practise, of enlisting young men to do the drudgery or render material aid, and then, in some cases, neglecting to give them proper credit.

The first memoir or paper published on a zoölogical subject by Lamarck was a modest one on shells, which appeared in 1792 in the _Journal d'Histoire naturelle_, the editors of which were Lamarck, Bruguière, Olivier, Haüy, and Pelletier. This paper was a review of an excellent memoir by Bruguière, who preceded Lamarck in the work of dismemberment of the Linnæan genera. His next paper was on four new species of Helix. To this _Journal_, of which only two volumes were published, Cuvier contributed his first paper--namely, on some new species of "Cloportes" (Oniscus, a genus of terrestrial crustacea or "pill-bugs"); this was followed by his second memoir on the anatomy of the limpet, his next article being descriptions of two species of flies from his collection of insects.[120] Seven years later Lamarck gave some account of the genera of cuttlefishes. His first general memoir was a prodromus of a new classification of shells (1799).

Meanwhile Lamarck's knowledge of shells and corals was utilized by Cuvier in his _Tableau élémentaire_, published in 1798, who acknowledges in the preface that in the exposition of the genera of shells he has been powerfully seconded, while he indicated to him (Cuvier) a part of the subgenera of corals and alcyonarians, and adds, "I have received great aid from the examination of his collection." Also he acknowledges that he had been greatly aided (_puissamment secondé_) by Lamarck, who had even indicated the most of the subdivisions established in his _Tableau élémentaire_ for the insects (Blainville, _l. c._, p. 129), and he also accepted his genera of cuttlefishes.

After this Lamarck judiciously refrained from publishing descriptions of new species, and other fragmentary labors, and for some ten years from the date of publication of his first zoölogical article reserved his strength and elaborated his first general zoölogical work, a thick octavo volume of 452 pages, entitled _Système des Animaux sans Vertèbres_, which appeared in 1801.

Linné had divided all the animals below the vertebrates into two classes only, the Insecta and Vermes, the insects comprising the present classes of insects, Myriapoda, Arachnida, and Crustacea; the Vermes embracing all the other invertebrate animals, from the molluscs to the monads.

Lamarck perceived the need of reform, of bringing order out of the chaotic mass of animal forms, and he says (p. 33) that he has been continually occupied since his attachment to the museum with this reform.

He relies for his characters, the fundamental ones, on the organs of respiration, circulation, and on the form of the nervous system. The reasons he gives for his classification are sound and philosophical, and presented with the ease and aplomb of a master of taxonomy.

He divided the invertebrates, which Cuvier had called animals with white blood, into the seven following classes.

We place in a parallel column the classification of Cuvier in 1798.

_Classification of Lamarck._ _Classification of Cuvier._

1. Mollusca. I. _Mollusca._

2. Crustacea. II. _Insectes et Vers._

3. Arachnides (comprising 1. Insectes. the Myriapoda). 2. Vers.

4. Insectes. III. _Zoophytes._

5. Vers. 1. Echinodermes. 2. Meduses, Animaux 6. Radiaires. infusorines, Rotifer, Vibrio, Volvox. 7. Polypes. 3. Zoophytes proprement dits.

Of these, four were for the first time defined, and the others restricted. It will be noticed that he separates the Radiata (_Radiaires_) from the Polypes. His "Radiaires" included the Echinoderms (the _Vers echinoderms_ of Bruguière) and the Medusæ (his _Radiaires molasses_), the latter forming the Discophora and Siphonophora of present zoölogists. This is an anticipation of the division by Leuckart in 1839 of the Radiata of Cuvier into Coelenterata and Echinodermata.

The "Polypes" of Lamarck included not only the forms now known as such, but also the Rotifera and Protozoa, though, as we shall see, he afterwards in his course of 1807 eliminated from this heterogeneous assemblage the Infusoria.

Comparing this classification with that of Cuvier[121] published in 1798, we find that in the most important respects, _i.e._, the foundation of the classes of Crustacea, Arachnida, and Radiata, there is a great advance over Cuvier's system. In Cuvier's work the molluscs are separated from the worms, and they are divided into three groups, Cephalopodes, Gasteropodes, and Acephales--an arrangement which still holds, that of Lamarck into Mollusques céphalés and Mollusques acéphalés being much less natural. With the elimination of the Mollusca, Cuvier allowed the Vers or Vermes of Linné to remain undisturbed, except that the Zoöphytes, the equivalent of Lamarck's Polypes, are separately treated.

He agrees with Cuvier in placing the molluscs at the head of the invertebrates, a course still pursued by some zoölogists at the present day. He states in the _Philosophie Zoologique_[122] that in his course of lectures of the year 1799 he established the class of Crustacea, and adds that "although this class is essentially distinct, it was not until six or seven years after that some naturalists consented to adopt it." The year following, or in his course of 1800, he separated from the insects the class of Arachnida, as "easy and necessary to be distinguished." But in 1809 he says that this class "is not yet admitted into any other work than my own."[123] As to the class of Annelides, he remarks: "Cuvier having discovered the existence of arterial and venous vessels in different animals which have been confounded under the name of worms (_Vers_) with other animals very differently organized, I immediately employed the consideration of this new fact in rendering my classification more perfect, and in my course of the year 10 (1802) I established the class of Annelides, a class which I have placed after the molluscs and before the crustaceans, as their known organization requires." He first established this class in his _Recherches sur les corps vivans_ (1802), but it was several years before it was adopted by naturalists.

The next work in which Lamarck deals with the classification of the invertebrates is his _Discours d'ouverture du Cours des Animaux sans Vertèbres_, published in 1806.

On page 70 he speaks of the animal chain or series, from the monad to man, ascending from the most simple to the most complex. The monad is one of his _Polypes amorphs_, and he says that it is the most simple animal form, the most like the original germ (_ébauche_) from which living bodies have descended. From the monad nature passes to the Volvox, Proteus (Amoeba), and Vibrio. From them are derived the _Polypes rotifères_ and other "Radiaires," and then the Vers, Arachnides, and Crustacea. On page 77 a tabular view is presented, as follows:

1. _Les Mollusques._ 2. _Les Cirrhipèdes._ 3. _Les Annelides._ 4. _Les Crustacés._ 5. _Les Arachnides._ 6. _Les Insectes._ 7. _Les Vers._ 8. _Les Radiaires._ 9. _Les Polypes._

It will be seen that at this date two additional classes are proposed and defined--_i.e._, the Annelides and the Cirrhipedes, though the class of Annelida was first privately characterized in his lectures for 1802.

The elimination of the barnacles or Cirrhipedes from the molluscs was a decided step in advance, and was a proof of the acute observation and sound judgment of Lamarck. He says that this class is still very imperfectly known and its position doubtful, and adds: "The Cirrhipedes have up to the present time been placed among the molluscs, but although certain of them closely approach them in some respects, they have a special character which compels us to separate them. In short, in the genera best known the feet of these animals are distinctly articulated and even crustaceous (_crustacés_)." He does not refer to the nervous system, but this is done in his next work. It will be remembered that Cuvier overlooked this feature of the jointed limbs, and also the crustaceous-like nervous system of the barnacles, and allowed them to remain among the molluscs, notwithstanding the decisive step taken by Lamarck. It was not until many years after (1830) that Thompson proved by their life-history that barnacles are true crustacea.

In the _Philosophie zoologique_ the ten classes of the invertebrates are arranged in the following order:

_Les Mollusques._ _Les Cirrhipèdes._ _Les Annelides._ _Les Crustacés._ _Les Arachnides._ _Les Insectes._ _Les Vers._ _Les Radiaires._ _Les Polypes._ _Les Infusoires._

At the end of the second volume Lamarck gives a tabular view on a page by itself (p. 463), showing his conception of the origin of the different groups of animals. This is the first phylogeny or genealogical tree ever published.

TABLEAU

Servant à montrer l'origine des differens animaux.

Vers. Infusoires. . Polypes. . Radiaires. . . . . . . . . Insectes. . Arachnides. Annelides. Crustacés. Cirrhipèdes. Mollusques. . . . Poissons. Reptiles. . . . . . Oiseaux. . . . . . Monotrèmes. M. Amphibies. . . . . . . . M. Cétacés. . . . M. Ongulés. M. Onguiculés.

The next innovation made by Lamarck in the _Extrait du Cours de Zoologie_, in 1812, was not a happy one. In this work he distributed the fourteen classes of the animal kingdom into three groups, which he named _Animaux Apathiques_, _Sensibles_, and _Intelligens_. In this physiologico-psychological base for a classification he unwisely departed from his usual more solid foundation of anatomical structure, and the results were worthless. He, however, repeats it in his great work, _Histoire naturelle des Animaux sans Vertèbres_ (1815-1822).

The sponges were by Cuvier, and also by Lamarck, accorded a position among the Polypes, near Alcyonium, which represents the latter's _Polypiers empâtés_; and it is interesting to notice that, for many years remaining among the Protozoa, meanwhile even by Agassiz regarded as vegetables, they were by Haeckel restored to a position among the Coelenterates, though for over twenty years they have by some American zoölogists been more correctly regarded as a separate phylum.[124] Lamarck also separated the seals and morses from the cetacea. Adopting his idea, Cuvier referred the seals to an order of carnivora.

Another interesting matter, to which Professor Lacaze-Duthiers has called attention in his interesting letter on p. 77, is the position assigned _Lucernaria_ among his _Radiaires molasses_ near what are now Ctenophora and Medusæ, though one would have supposed he would, from its superficial resemblance to polyps, have placed it among the polyps. To Lamarck we are also indebted for the establishment in 1818 of the molluscan group of Heteropoda.

Lamarck's acuteness is also shown in the fact that, whereas Cuvier placed them among the acephalous molluscs, he did not regard the ascidians as molluscs at all, but places them in a class by themselves under the name of _Tunicata_, following the Sipunculus worms. Yet he allowed them to remain near the Holothurians (then including Sipunculus) in his group of _Radiaires echinodermes_, between the latter and the Vers. He differs from Cuvier in regarding the tunic as the homologue of the shell of Lamellibranches, remarking that it differs in being muscular and contractile.

Lamarck's fame as a zoölogist rests chiefly on this great work. It elicited the highest praise from his contemporaries. Besides containing the innovations made in the classification of the animal kingdom, which he had published in previous works, it was a summary of all which was then known of the invertebrate classes, thus forming a most convenient hand-book, since it mentioned all the known genera and all the known species except those of the insects, of which only the types are mentioned. It passed through two editions, and still is not without value to the working systematist.

In his _Histoire des Progrès des Sciences naturelles_ Cuvier does it justice. Referring to the earlier volume, he states that "it has extended immensely the knowledge, especially by a new distribution, of the shelled molluscs ... M. de Lamarck has established with as much care as sagacity the genera of shells." Again he says, in noticing the three first volumes: "The great detail into which M. de Lamarck has entered, the new species he has described, renders his work very valuable to naturalists, and renders most desirable its prompt continuation, especially from the knowledge we have of means which this experienced professor possesses to carry to a high degree of perfection the enumeration which he will give us of the shells" (_Oeuvres complètes de Buffon_, 1828, t. 31, p. 354).

"His excellences," says Cleland, speaking of Lamarck as a scientific observer, "were width of scope, fertility of ideas, and a preëminent faculty of precise description, arising not only from a singularly terse style, but from a clear insight into both the distinctive features and the resemblance of forms" (_Encyc. Britannica_, Art. LAMARCK).

The work, moreover, is remarkable for being the first one to begin with the simplest and to end with the most highly developed forms.

Lamarck's special line of study was the Mollusca. How his work is still regarded by malacologists is shown by the following letter from our leading student of molluscs, Dr. W. H. Dall:

"SMITHSONIAN INSTITUTION, "UNITED STATES NATIONAL MUSEUM, WASHINGTON, D. C., "_November 4, 1899._

"Lamarck was one of the best naturalists of his time, when geniuses abounded. His work was the first well-marked step toward a natural system as opposed to the formalities of Linné. He owed something to Cuvier, yet he knew how to utilize the work in anatomy offered by Cuvier in making a natural classification. His failing eyesight, which obliged him latterly to trust to the eyes of others; his poverty and trials of various kinds, more than excuse the occasional slips which we find in some of the later volumes of the _Animaux sans Vertèbres_. These are rather of the character of typographical errors than faults of scheme or principle.

"The work of Lamarck is really the foundation of rational natural malacological classification; practically all that came before his time was artificial in comparison. Work that came later was in the line of expansion and elaboration of Lamarck's, without any change of principle. Only with the application of embryology and microscopical work of the most modern type has there come any essential change of method, and this is rather a new method of getting at the facts than any fundamental change in the way of using them when found. I shall await your work on Lamarck's biography with great interest.

"I remain, "Yours sincerely, "WILLIAM H. DALL."

FOOTNOTES:

[119] During the same period (1803-1829) Russia sent out expeditions to the North and Northeast, accompanied by the zoölogists Tilesius, Langsdorff, Chamisso, Eschscholtz, and Brandt, all of them of German birth and education. From 1823 to 1850 England fitted up and sent out exploring expeditions commanded by Beechey, Fitzroy, Belcher, Ross, Franklin, and Stanley, the naturalists of which were Bennett, Owen, Darwin, Adams, and Huxley. From Germany, less of a maritime country, at a later date, Humboldt, Spix, Prince Wied-Neuwied, Natterer, Perty, and others made memorable exploring expeditions and journeys.

[120] These papers have been mercilessly criticised by Blainville in his "Cuvier et Geoffroy St. Hilaire." In the second article--_i.e._, on the anatomy of the limpet--Cuvier, in considering the organs, follows no definite plan; he gives a description "_tout-a-fait fantastique_" of the muscular fibres of the foot, and among other errors in this first essay on comparative anatomy he mistakes the tongue for the intromittent organ; the salivary glands, and what is probably part of the brain, being regarded as the testes, with other "_erreurs matérielles inconcevables, même à l'époque ou elle fut rédigée_." In his first article he mistakes a species of the myriapod genus Glomeris for the isopod genus Armadillo. In this he is corrected by the editor (possibly Lamarck himself), who remarks in a footnote that the forms to which M. Cuvier refers under the name of Armadillo are veritable species of Julus. We have verified these criticisms of Cuvier by reference to his papers in the "Journal." It is of interest to note, as Blainville does, that Cuvier at this period admits that there is a passage from the Isopoda to the armadilloes and Julus. Cuvier, then twenty-three years old, wrote: "_Nous sommes donc descendus par degrès, des Écrevisses aux Squilles, de celles-ci aux Aselles, puis aux Cloportes, aux Armadilles et aux Ïules_" (_Journal d'Hist. nat._, tom. ii., p. 29, 1792). These errors, as regards the limpet, were afterwards corrected by Cuvier (though he does not refer to his original papers) in his _Mémoires pour servir à l'Histoire et à l'Anatomie des Mollusques_ (1817).

[121] _Tableau élémentaire de l'Histoire naturelle des Animaux._ Paris, An VI. (1798). 8vo, pp. 710. With 14 plates.

[122] Tome i., p. 123.

[123] In his _Histoire des Progrès des Sciences naturelles_ Cuvier takes to himself part of the credit of founding the class Crustacea, stating that Aristotle had already placed them in a class by themselves, and adding, "_MM. Cuvier et de Lamarck les en out distingués par des caractères de premier ordre tirés de leur circulation._" Undoubtedly Cuvier described the circulation, but it was Lamarck who actually realized the taxonomic importance of this feature and placed them in a distinct class.

[124] See A. Hyatt's _Revision of North American Poriferæ_, Part II. (Boston, 1877, p. 11); also the present writer in his _Text-book of Zoölogy_ (1878).