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.
Fig. 170.—Pescado blanco, Chirostoma humboldtianum (Val.). Lake Chalco, City of Mexico.
Fig. 171.—Silverside or Brit, Kirtlandia vagrans (Goode & Bean). Pensacola.
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.
Fig. 172.—Blue Smelt or Pez del Rey, Atherinopsis californiensis Girard. San Diego.
Fig. 173.—Flower of the waves, Iso flos-maxis, Jordan & Starks. Enoshima, Japan.