CHAPTER XII

PERCESOCES AND RHEGNOPTERI

=SUBORDER Percesoces.=—In the line of direct ascending transition from the _Haplomi_ and _Synentognathi_, the pike and flying-fish, towards the typical perch-like forms, we find a number of families, perch-like in essential regards but having the ventral fins abdominal.

These types, represented by the mullet, the silverside, and the barracuda, have been segregated by Cope as an order called _Percesoces_ (Perca, perch; Esox, pike), a name which correctly describes their real affinities. In these typical forms, mullet, silverside, and barracuda, the affinities are plain, but in other transitional forms, as the threadfin and the stickleback, the relationships are less clear. Cope adds to the series of _Percesoces_ the _Ophiocephalidæ_, which Gill leaves with the _Anabantidæ_ among the spiny-rayed forms. Boulenger adds also the sand-lances (_Ammodytidæ_) and the threadfins (_Polynemidæ_), while Woodward places here the _Crossognathidæ_. In the present work we define the _Percesoces_ so as to include all spiny-rayed fishes in which the ventral fins are naturally abdominal, excepting those having a reduced number of gill-bones, or of actinosts, or other peculiarities of the shoulder-girdle. The _Ammodytidæ_ have no real affinities with the _Percesoces_. The _Crossognathidæ_ and other families with abdominal ventrals and the dorsal spines wholly obsolete may belong with the _Haplomi_. Boulenger places the _Chiasmodontidæ_, the _Stromateidæ_, and the _Tetragonuridæ_ among the _Percesoces_, an arrangement of very doubtful validity. In most of the _Percesoces_ the scales are cycloid, the spinous dorsal forms a short separate fin, and in all the air-duct is wanting.

=The Silversides: Atherinidæ.=—The most primitive of living _Percesoces_ constitute the large family of silversides (_Atherinidæ_), known as "fishes of the King," Pescados del Rey, Pesce Rey, or Peixe Re, wherever the Spanish or Portuguese languages are spoken. The species are, in general, small and slender fishes of dry and delicate flesh, feeding on small animals. The mouth is small, with feeble teeth. There is no lateral line, the color is translucent green, with usually a broad lateral band of silver. Sometimes this is wanting, and sometimes it is replaced by burnished black. Some of the species live in lakes or rivers, others in bays or arms of the sea, but never at a distance from the shore or in water of more than a few feet in depth. The larger species are much valued as food, the smaller ones, equally delicate, are fried in numbers as "whitebait," but the bones are firmer and more troublesome than in the smelts and young herring. The species of the genus _Atherina_, known as "friars," or "brit," are chiefly European, although some occur in almost all warm or temperate seas. These are small fishes, with the mouth relatively large and oblique and the scales rather large and firm. _Atherina hepsetus_ and _A. presbyter_ are common in Europe, _Atherina stipes_ in the West Indies, _Atherina bleekeri_ in Japan, and _Atherina insularum_ and _A. lacunosa_ in Polynesia. The genus _Chirostoma_ contains larger species, with projecting lower jaw, abounding in the lakes of Mexico. _Chirostoma humboldtianum_ is very abundant about Mexico City. Like all the other species of this genus it is remarkably excellent as food, the different species constituting the famous "Pescados Blancos" of the great lakes of Chapala and Patzcuaro of the western slope of Mexico. A very unusual circumstance is this: that numerous very closely related species occupy the same waters and are taken in the same nets. In zoology, generally, it is an almost universal rule that very closely related species occupy different geographical areas, their separation being due to barriers which prevent interbreeding. But in the lake of Chapala, near Guadalajara, Prof. John O. Snyder and the present writer, and subsequently Dr. S. E. Meek, found ten distinct species of _Chirostoma_, all living together, taken in the same nets and scarcely distinguishable except on careful examination. Most of these species are very abundant throughout the lake, and all reach a length of twelve to fifteen inches. These species are _Chirostoma estor_, _Ch. lucius_, _Ch. sphyræna_, _Ch. ocotlane_, _Ch. lermæ_, _Ch. chapalæ_, _Ch. grandocule_, _Ch. labarcæ_, _Ch. promelas_, and _Ch. bartoni_. A similar assemblage of species nearly all different from these was obtained by Dr. Seth E. Meek in the lake of Patzcuaro, farther south. In this lake were found _Ch. attenuatum_, _Ch. patzcuaro_, _Ch. humboldtianum_, _Ch. grandocule_, and _Ch. estor_. The lake of Zirahuen, near Chapala, contains _Ch. estor_ and _Ch. zirahuen_.

Still another species, _Ch. jordani_, is found about the city of Mexico, where it is sold baked in corn-husks. Along the coasts of Peru, Chile, and Argentina is found still another assemblage of fishes of the king, with very small scales, constituting the genera _Basilichthys_ and _Gastropterus_ (_Pisciregia_). _Basilichthys microlepidotus_ is the common Pesca del Rey of Chile. The small silversides, or "brit," of our Atlantic coast belong to numerous species of _Menidia_, _Menidia notata_ to the northward and _Menidia menidia_ to the southward being most abundant. _Kirtlandia laciniata_, with ragged scales, is common along the Virginia coast, and _K. vagrans_ farther south. Another small species, very slender and very graceful, is the brook silverside _Labidesthes sicculus_, which swarms in clear streams from Lake Ontario to Texas. This species, three to four inches long, has the snout produced and a very bright silvery stripe along the side. Large and small species of silversides occur in the sea along the California coast, where they are known familiarly as "blue smelt" or "Peixe Re." The most important of these and the largest member of the family, reaching a length of eighteen inches, is _Atherinopsis californiensis_, an important food-fish throughout California, everywhere wrongly known as smelt. _Atherinops affinis_ is much like it, but has Y-shaped teeth. _Iso flos-maris_, called Nami-no-hana, or flower of the surf, is a shining little fish with belly shape like that of a herring. It lives in the surf on the coast of Japan. _Melanotænia nigrans_ of Australia (family _Melanotæniidæ_) has the lateral band jet-black, as has also _Melaniris balsanus_ of the rivers of southern Mexico. _Atherinosoma vorax_ of Australia has strong teeth like those of a barracuda.

Fossil species of _Atherina_ occur in the Italian Eocene, the best known being _Atherina macrocephala_. Another species, _Rhamphognathus paralepoides_, allied to _Menidia_, occurs in the Eocene of Monte Bolca.

=The Mullets: Mugilidæ.=—The mullets (_Mugilidæ_) are more clumsy in form than the silversides, robust, with broad heads and stouter fin-spines. The ventral fins are abdominal but well forward, the pelvis barely touching the clavicle, a condition to be defined as "subabdominal." The small mouth is armed with very feeble teeth, often reduced to mere fringes. The stomach is muscular like the gizzard of a fowl and the species feed largely on the vegetation contained in mud. There are numerous species, mostly living in shallow bays and estuaries, but some of them are confined to fresh waters. All are valued as food and some of them under favorable conditions are especially excellent.

Most of the species belong to the genera _Mugil_, the mullet of all English-speaking people, although not at all related to the red mullet or surmullet of the ancient Romans, _Mullus barbatus_.

The mullets are stoutish fish from one to two feet long, with blunt heads, small mouths almost toothless, large scales, and a general bluish-silvery color often varied by faint blue stripes. The most important species is _Mugil cephalus_, the common striped mullet. This is found throughout southern Europe and from Cape Cod to Brazil, from Monterey, California, to Chile, and across the Pacific to Hawaii, Japan, and the Red Sea. Among specimens from all these regions we can detect no difference.

Professor Goode gives the following account of its habits:

"The large mullets begin to assemble along the Florida coast in schools in the height of summer, probably preparatory to spawning, and at this time the eggs commence to mature. In this season they swim at the surface, and are then pursued by enemies in the water and the air, and also fall an easy prey to the fishermen. They appear to prefer to swim against the wind, and school best with a northeast wind. They also run against the tide. In Florida the spawning season seems to extend from the middle of November to the middle of January. Some of the fishermen say that they go on the mud-flats and oyster-beds at the mouth of the river to deposit their eggs. What becomes of them after this no one seems to know, but it is probable that they spread themselves over the whole surface of water-covered country in such a manner as not to be perceptible to the fisherman, who makes no effort at this time to secure the spent, lean fish. Many of them probably find their way to the lakes and others remain wherever they find good feeding-ground, gathering flesh and recruiting strength for the great strain of the next spawning season."

Professor Goode informs us that the fishermen recognize "three distinct periods of schooling and separate runs of mullet. To what extent these are founded on tradition, or upon the necessity of change in the size of the mesh of their nets, it is impossible to say. The 'June mullet' average about five to the pound; the 'fat mullet,' which are taken from August 20 to October 1, weigh about two pounds; these have, the fishermen say, a 'roe of fat' on each side as thick as a man's thumb. The 'roe mullet' weigh about two and a half pounds and are caught in November and until Christmas. Between the seasons of 'fat mullet' and 'roe mullet' there is an intermission of two or three weeks in the fishing." Professor Goode hazards the suggestion that "the 'fat mullet' of September are the breeding fish of November, with roes in an immature state, the ova not having become fully differentiated."

The mullet feed on the bottom in quiet water, swimming head downward. The food is sifted over in the mouth, the mud rejected, and the plants, chiefly microscopic, retained. Mr. Silas Stearns compares a school of mullets to barnyard fowls feeding together. When a fish finds a rich spot the others flock about it as chickens do. The pharyngeals form a sort of filter, stopping the sand and mud, the coarse parts being ejected through the mouth. Dr. Günther thus describes this apparatus:

"The upper pharyngeals have a rather irregular form: they are slightly arched, the convexity being directed toward the pharyngeal cavity, tapering anteriorly and broad posteriorly. They are coated with a thick, soft membrane, which reaches far beyond the margin of the bone and is studded all over with minute horny cilia. Each branchial arch is provided with a series of long gill-rakers, which are laterally bent downward, each series closely fitting to the sides of the adjoining arch; they constitute together a sieve admirably adapted to permit a transit for the water, retaining at the same time every solid substance in the cavity of the pharynx."

The young mullet feed in schools and often swim with the head at the surface of the water.

We are not able to distinguish from the common striped mullet of Europe and America the mullet of Hawaii, the famous Ama-ama, the most valued of Hawaiian fishes. This species is reared in mullet ponds, made by extending a stone wall across an arm of the sea. Through openings in the wall the young mullet enter, and in its protection they grow very fat on the abundant algæ and other vegetation. They thus become the most plentiful and most esteemed of the market fishes of Honolulu. The Awa (_Chanos_) and the Awa-awa (_Elops_) also enter these ponds and are reared with the mullet, being similarly but less valued. Unfortunately the kaku, or small barracuda (_Sphyræna helleri_), also enters with these helpless fishes and destroys many of the smaller individuals. Another striped species, also very similar to _Mugil cephalus_ in appearance and value, in fact indistinguishable from the Hawaiian mullet, abounds in Japan and India.

The white or unstriped mullets are generally smaller, but otherwise differ little. _Mugil curema_ is the white mullet of tropical America, ranging occasionally northward, and several other species occur in the West Indies and the Mediterranean. The genus _Mugil_ has the eye covered by thick transparent tissue called the adipose eyelid. In _Liza_ the adipose eyelid is wanting. _Liza capito_, the big-headed mullet of the Mediterranean, is a well-known species. Most of the mullets of the south seas belong to the genus _Liza_. _Liza melinoptera_ and _Liza_ _cæruleomaculata_ are common in Samoa. The genus _Querimana_ includes dwarf-mullets, two or three inches long, known as whirligig-mullets. These little fishes gather in small schools and swim round and round on the surface like the whirligig-beetles, or _Gyrinidæ_, their habits being like those of the young mullets; some young mullets having been, in fact, described as species of _Querimana_. The genus _Agonostomus_ includes fresh-water mullets of the mountain rivers of the East and West Indies and Mexico, locally known as trucha, or trout. _Agonostomus nasutus_ of Mexico is the best-known species.

The Joturo, or Bobo, _Joturus pichardi_, is a very large robust and vigorous mullet which abounds at the foot of waterfalls in the mountain torrents of Cuba, eastern Mexico, and Central America. It is a good food-fish, frequently taken about Jalapa, Havana, and on the Isthmus of Panama. Its lips are very thick and its teeth are broad, serrated, loosely inserted incisors.

Fossil mullets are few. _Mugil radobojanus_ is the earliest from the Miocene of Croatia.

=The Barracudas: Sphyrænidæ.=—The _Sphyrænidæ_, or barracudas, differ from the mullets in the presence of very strong teeth in the bones of the large mouth. The lateral line is also developed, there is no gizzard, and there are numerous minor modifications connected with the food and habits. The species are long, slender swift fishes, powerful in swimming and voracious to the last degree. Some of the species reach a length of six feet or more, and these are almost as dangerous to bathers as sharks would be. The long, knife-like teeth render them very destructive to nets. The numerous species are placed in the single genus _Sphyræna_, and some of them are found in all warm seas, where they feed freely on all smaller fishes, their habits in the sea being much like those of the pike in the lakes. The flesh is firm, delicate, and excellent in flavor. In the larger species, especially in the West Indies, it may be difficult of digestion and sometimes causes serious illness, or "ichthyosism."

_Sphyræna sphyræna_ is the spet, or sennet, a rather small barracuda common in southern Europe. _Sphyræna borealis_ of our eastern coast is a similar but still feebler species rarely exceeding a foot in length. These and other small species are feeble folk as compared with the great barracuda (_Sphyræna barracuda_) of the West Indies, a robust savage fish, also known as picuda or becuna. _Sphyræna commersoni_ of Polynesia is a similar large species, while numerous lesser ones occur through the tropical seas. On the California coast _Sphyræna argentea_ is an excellent food-fish, slenderer than the great barracuda but reaching a length of five feet.

Several species of fossil barracuda occur in the Italian Eocene, _Sphyræna bolcensis_ being the earliest.

=Stephanoberycidæ.=—We may append to the _Percesoces_, for want of a better place, a small family of the deep sea, its affinities at present unknown. The _Stephanoberycidæ_ have the ventrals I, 5, subabdominal, a single dorsal without spine, and the scales cycloid, scarcely imbricated, each with one or two central spines. The mouth is large, with small teeth, the skull cavernous, as in the berycoids, from which group the normally formed ventrals abdominal in position would seem to exclude it. _Stephanoberyx monæ_ and _S. gilli_ are found at the depth of a mile and a half below the Gulf Stream. Boulenger first placed them with the _Percesoces_, but more recently suggests their relationship with the _Haplomi_. Perhaps, as supposed by Gill, they may prove to be degenerate berycoids in which the ventral fins have lost their normal connection.

=Crossognathidæ.=—A peculiar primitive group referred by Woodward to the _Percesoces_ is the family of _Crossognathidæ_ of the Cretaceous period. As in these fishes there are no fin-spines, they may be perhaps better placed with the _Haplomi_. The dorsal fin is long, without distinct spines, and the abdominal ventrals have six to eight rays. The mouth is small, with feeble teeth, and the body is elongate and compressed. _Crossognathus sabandianum_ occurs in the Cretaceous of Switzerland and Germany, _Syllæmus latifrons_ and other species in the Colorado Cretaceous, and _Syllæmus anglicus_ in England. The _Crossognathidæ_ have probably the lower pharyngeals separate, else they would be placed among the _Synentognathi_, a group attached by Woodward, not without reason, to the _Percesoces_.

=Cobitopsidæ.=—Near the _Crossognathidæ_ may be placed the extinct _Cobitopsidæ_, _Cobitopsis acuta_ being recorded from the Oligocene of Puy-de-Dôme in France. In this species there is a short dorsal fin of about seventeen rays, no teeth, and the well-developed ventral fins are not far in front of the anal. This little fish bears a strong resemblance to _Ammodytes_, but the affinities of the latter genus are certainly with the ophidioid fishes, while the real relationship of _Cobitopsis_ is uncertain.

=Suborder Rhegnopteri.=—The threadfins (_Polynemidæ_) are allied to the mullets, but differ from them and from all other fishes in the structure of the pectoral fin and its basal bones, or actinosts.

The pectoral fin is divided into two parts, the lower composed of free or separate rays very slender and thread-like, sometimes longer than the body. Two of the actinosts of the pectoral support the fin, one is slender and has no rays, while the fourth is plate-like and attached to the coracoids, supporting the pectoral filaments. The body is rather robust, covered with large scales, formed much as in the mullet. The lateral line extends on the caudal fin as in the _Sciænidæ_ which group these fishes resemble in many ways. The mouth is large, inferior, with small teeth. The species are carnivorous fishes of excellent flesh, abounding on sandy shores in the warm seas. They are not very active and not at all voracious. The coloration is bluish and silvery, sometimes striped with black. Most of the species belong to the genus _Polydactylus_. _Polydactylus virginicus_, the barbudo, with seven filaments, is common in the West Indies and Florida. _Polydactylus octonemus_ with eight filaments is more rare, but ranges further north. _Polydactylus approximans_, the raton of western Mexico, with six filaments, reaches San Diego. _Polydactylus plebejus_ is common in Japan and other species range through Polynesia. In India isinglass is made from the large air-bladder of species of _Polydactylus_. The rare _Polynemus quinquarius_ of the West Indies have five pectoral filaments, these being greatly elongate, much longer than the body.

No extinct _Polynemidæ_ are recorded.