PISCES. 235 
and the lower part of Chesapeake Bay. They are called bow-fin 
in Lake Champlain, dog-fish in Lake Erie, mud-fish in South Caro- 
lina, &c. 
The next family, the Savromei, embraces but two genera, Lepidosteus 
and Polypterus, both recent. The genus Lepidosteus is confined to North 
America, where it is represented by about ten species peculiar to different 
sections of country. There are two types of structure in Lepidosteus, one 
with broad short jaws, the other with the jaws very narrow and elongated. 
The dorsal is single, and placed far back opposite to the anal; and the 
whole appearance, at first sight, is not unlike a pike, for which reason one 
species was called by Linneus Hsox osseus, or bony pike. The air- 
bladder presents a cellular character, somewhat like that of Amia. The 
principal osteological features consist in the vomer being divided into two; 
an upper jaw composed of many pieces, a lower jaw similar in structure to 
some Reptilia, as also in the vertebree, one of whose articulations is convex, 
the other concave. There are two series of imbricated spines on the 
anterior ray of each fin, the remaining rays being jointed. The scales are 
combined into an impenetrable coat of mail, of almost adamantine 
hardness ; and the jaws being provided with large conical teeth, with smaller 
ones interspersed, and on the vomer, give the gar-fish, or gar-pike, a truly 
formidable appearance. Gars attain a Jarge size, especially the broad-billed 
species, which has been known to measure ten feet in length. When of 
proportions like this, it justly deserves the name of “ Alligator Gar,” from 
the striking resemblance borne by the head to that of the alligator. It 
would carry us too far out of our limits to extend these observations to the 
remaining structural peculiarities of this highly remarkable and unique 
genus, which ranges the waters of America, an isolated memorial of a past 
generation. 
The genus Polypterus, by some justly made the type of a distinct family, 
consists of four species, found only in the rivers of Africa. The most 
striking external feature, by which it is distinguished from its nearest 
ally, the preceding genus, is to be found in the great number of separate 
finlets along the back, each consisting of a spine with some posterior rays. 
The body is enveloped in mailed scales, of great hardness, as in Lepidosteus. 
The upper jaw is undivided ; the lower, fish-like, not reptilian; the vomer is 
simple ; the vertebre bi-concave ; and the fins without imbrications. 
The remaining families of the Holostean ganoids are all extinct; and 
we shall therefore confine ourselves to a brief synopsis only of their 
characters. But few of the species, hitherto described, belong to North 
America: these will be referred to in the proper place. 
The Rosrrati have a greatly elongated body, the head running out into 
a narrow snout. The vertebral column is not much developed, only the 
heal and the ribs being ossified. The dorsal and anal fins are of great 
development. The scales are variable in shape and number. 
The Pycnoponres were fish of medium, or considerable size, with a short, 
high, and much compressed body. The caudal fin alone is well developed ; 
the dorsal and anal, which begin in the middle of the body and extend to 
439 
