CHAPTER XXVIII

SUBORDER JUGULARES

=THE Jugular-fishes.=—In all the families of spiny-rayed fishes, as ranged in order in the present work, from the _Berycidæ_ to the _Soleidæ_, the ventrals are thoracic in position, the pelvis, if present, being joined to the shoulder-girdle behind the symphysis of the clavicles so that the ventral fin falls below or behind the pectoral fin. To this arrangement the families of _Bembradidæ_ and _Pinguipedidæ_ offer perhaps the only exceptions.

In all the families which precede the _Berycidæ_ in the linear series adopted in this work, the ventral fins when present are abdominal, the pelvis lying behind the clavicles and free from them as in the sharks, the reptiles, and all higher vertebrates.

In all the families remaining for discussion, the ventrals are brought still farther forward to a point distinctly before the pectorals. This position is called jugular (Lat. _jugulum_, throat).

The fishes with jugular ventrals we here divide into six groups, orders, and suborders: _Jugulares_, _Haplodoci_, _Xenopterygii_, _Anacanthini_, _Opisthomi_, and _Pediculati_. The last two groups, and perhaps the _Anacanthini_ also, may well be considered as distinct orders, being more aberrant than the others.

For the most primitive and at the same time most obscurely defined of these groups we may retain the term applied by Linnæus to all of them, the name _Jugulares_. This group includes those jugular-fishes in which the position of the gills, the structure of the skull, and the form of the tail are essentially as in ordinary fishes. It is an extremely diversified and perhaps unnatural group, some of its members resembling _Opisthognathidæ_ and _Malacanthidæ_, others suggesting the mailed-cheek fishes, and still others more degenerate. The fishes having the fins thus placed were long ago set apart by Linnæus, under the name of "Jugulares," _Callionymus_ being the genus first placed by him in this group. Besides their anterior insertion, the ventrals in the _Jugulares_ are more or less reduced in size, the rays being usually but not always less than I, 5 in number and more often reduced to one or two, or even wholly lost.

In general, the jugular fishes are degenerate as compared with the perch-like forms, but in certain regards they are often highly specialized. The groups showing this character are probably related one to another, but in some cases this fact is not clearly shown. In most of the jugular-fishes the shoulder-girdle shows some change or distortion. The usual foramen in the hypercoracoid is often wanting or relegated to the interspace between the coracoids, and the arrangement of the actinosts often deviates from that seen in the perciform fishes.

=The Weevers: Trachinidæ.=—Of the various families the group of weevers, _Trachinidæ_, most approaches the type of ordinary fishes. In the words of Dr. Gill, these fishes are known by "an elongated body attenuated backward from the head, compressed, oblong head, with the snout very short, a deeply cleft, oblique mouth, and a long spine projecting backward from each operculum and strengthened by extension on the surface of the operculum, as a keel. The dorsal fins are distinct, the first composed of strong, pungent spines radiating from a short base and about six or seven in number. The second dorsal and anal are very long. The pectorals have the lower rays unbranched, and the ventrals are in advance of the pectorals, and have each a spine and five rays. The species of this family are mostly found along the European and western African coast; but singularly enough a species closely related to the Old World form is found on the coast of Chile. None have been obtained from the intermediate regions or from the American coast. Two species are found in England, and are known under the name of the greater weever (_Trachinus draco_), about twelve inches long, and the lesser weever (_Trachinus vipera_), about six inches long. They are perhaps the most dreaded of the smaller English fishes. The formidable opercular spines are weapons of defense, and when seized by the fisherman the fish is apt to throw its head in the direction of the hand and lance a spine into it. The pungent dorsal spines are also defensive. Although without a poison gland, such as some fishes distantly related have at the base of the spines, they cause very severe wounds, and death may occur from tetanus. They are therefore divested of both opercular and dorsal spines before being exposed for sale. The various popular names which the weevers enjoy, in addition to their general designation, mostly refer to the armature of the spines, or are the result of the armature; such are adder-fish, stingfish, and sting-bull."

No species of _Trachinidæ_ is known from North America or from Asia. In these fishes, as Dr. Boulenger has lately shown, the hypercoracoid is without foramen, the usual perforation lying between this bone and the hypercoracoid. A similar condition exists in the _Anacanthini_, or codfishes, but it seems to have been developed independently in the two groups. In the relatives of the _Trachinidæ_ the position of this foramen changes gradually, moving by degrees from its usual place to the lower margin of the hypercoracoid. Species referred to _Trachinus_ are recorded from the Miocene as well as _Trachinus_.

The extinct group of _Callipterygidæ_ found in the Eocene of Monte Bolca seems allied to the _Trachinidæ_. It has the dorsal fin continuous, the spines small, the soft rays high; the scales are very small or wanting. _Callipteryx speciosus_ and _C. recticandus_ are the known species.

=The Nototheniidæ.=—In the family of _Nototheniidæ_ the foramen is also wanting or confluent with the suture between the coracoids. To this family belong many species of the Antarctic region. These are elongate fishes with ctenoid scales and a general resemblance to small _Hexagrammidæ_. In most of the genera there is more than one lateral line. These species are the antipodes of the _Cottidæ_ and _Hexagrammidæ_; although lacking the bony stay of the latter, they show several analogical resemblances and have very similar habits.

The _Harpagiferidæ_, naked, with the opercle armed with spines, and resemble sculpins even more closely than do the _Nototheniidæ_. _Harpagifer_ is found in Antarctic seas, and the three species of _Draconetta_ in the deeper waters of the North Atlantic and Pacific. These little fishes resemble _Callionymus_, but the opercle, instead of the preopercle, bears spines. The _Bovichthyidæ_ of New Zealand are also sculpin-like and perhaps belong to the same family. Dr. Boulenger places all these Antarctic forms with the foramen outside the hypercoracoid in one family, _Nototheniidæ_. Several deep-sea fishes of this type have been lately described by Dr. Louis Dollo and others from the Patagonian region. One of these forms, _Macrias amissus_, lately named by Gill and Townsend, is five feet long, perhaps the largest deep-sea fish known. The family of _Percophidæ_, from Chile, is also closely allied to these forms, the single species differing in slight respects of osteology.

Closely related to the family of _Nototheniidæ_ and perhaps scarcely distinct from it is the small family of _Pteropsaridæ_, which differs in having but one lateral line and the foramen just above the lower edge of the hypercoracoid. The numerous species inhabit the middle Pacific, and are prettily colored fishes, looking like gobies. _Pteropsaron_ is a Japanese genus, with high dorsal and anal fins; _Parapercis_ is more widely diffused. _Osurus schauinslandi_ is one of the neatest of the small fishes of Hawaii. Several species of _Parapercis_ and _Neopercis_ occur in Japan and numerous others in the waters of Polynesia. _Pseudeleginus majori_ of the Italian Miocene must belong near _Parapercis_.

The _Bathymasteridæ_, or ronquils, are perhaps allied to the _Nototheniidæ_; they resemble the _Opisthognathidæ_, but the jaws are shorter and they have a large number of vertebræ as befits their northern distribution. _Ronquilus jordani_ is found in Puget Sound and _Bathymaster signatus_ in Alaska. The ventral rays are I, 5, and the many-rayed dorsal has a few slender spines in front.

=The Leptoscopidæ.=—The _Leptoscopidæ_ of New Zealand resemble the weevers and star-gazers, but the head is unarmed, covered by thin skin.

=The Star-gazers: Uranoscopidæ.=—The _Uranoscopidæ_, or star-gazers, have the head cuboid, mostly bony above, the mouth almost vertical, the lips usually fringed, and the eyes on the flat upper surface of the head. The spinous dorsal is short and may be wanting. The hypercoracoid has a foramen, and the body is naked or covered with small scales. The appearance is eccentric, like that of some of the _Scorpænidæ_, but the anatomy differs in several ways from that of the mailed-cheek fishes.

The species inhabit warm seas, and the larger ones are food-fishes of some importance. One species, _Uranoscopus scaber_, abounds in the Mediterranean. _Uranoscopus japonicus_ and other species are found in Japan. _Astroscopus y-græcum_ is the commonest species on our Atlantic coast. The bare spaces on the top of the head in this species yield vigorous electric shocks. Another American species is _Astroscopus guttatus_. In Japan and the East Indies the forms are more numerous and varied. _Ichthyscopus lebeck_, with a single dorsal, is a fantastic inhabitant of the seas of Japan, and _Anema monopterygium_ in New Zealand.

_Uranoscopus peruzzii_, an extinct star-gazer, has been described from the Pliocene of Tuscany.

=The Dragonets: Callionymidæ.=—Remotely allied to the _Uranoscopidæ_ is the interesting family of dragonets, or _Callionymidæ_. These are small scaleless fishes with flat heads, the preopercle armed with a strong spine, the body bearing a general resemblance to the smaller and smoother _Cottidæ_. The gill-openings are very small, the ventral fins wide apart. The colors are highly variegated, the fins are high, often filamentous, and the sexes differ much in coloration and in the development of the fins. The species are especially numerous on the shores of Japan, where _Callionymus valenciennesi_, _Callionymus beniteguri_, and _Calliurichthys japonicus_ are food-fishes of some slight importance. Others are found in the East Indies, and several large and handsome forms are taken in the Mediterranean. _Callionymus draco_, the dragonet, or "sculpin," reaches the coast of England. In America but three species have been taken. These are dredged in deep water in the East Indies. In other parts of the world these fantastic little creatures are shore-fishes, creeping about in the shallow bays. Species of _Synchiropus_, colored like the coral sands, abound in the Polynesian coral reefs.

A fossil species of _Callionymus_ (_C. macrocephalus_) are found in the Miocene of Croatia.

The family of _Rhyacichthyidæ_ is a small group of Asiatic fishes allied to the _Callionymidæ_, but less elongate and differing in minor details. They are found not in the sea, but in mountain streams. _Rhyacichthys_ (formerly called by the preoccupied name _Platyptera_) is the principal genus.

The _Trichonontidæ_, with wide gill-openings and cycloid scales, are also related to the _Callionymidæ_. The species are few, small, and confined to the Indian and Australian seas. Another small family closely related to this is the group of _Hemerocœtidæ_ of the same region.

=The Dactyloscopidæ.=—In this and the preceding families of jugular fishes the ventral rays remain I, 5, as in the typical thoracic forms. In most of the families yet to be described the number is I, 3, a character which separates the little fishes of the family of _Dactyloscopidæ_ from the _Uranoscopidæ_ and _Leptoscopidæ_. _Dactyloscopus tridigitatus_ is a small fish of the coral sands of Cuba. The other species of this family are found mostly in the West Indies and on the west coast of Mexico. Several genera, _Myxodagnus_, _Gillellus_, _Dactylagnus_, etc., are recognized. In the structure of the shoulder-girdle these species diverge from the star-gazers, approaching the blennies, and their position is intermediate between _Trachinidæ_ and _Blenniidæ_.