MALACOPTERYGII ABDOMINALES. 205 



Anableps B1.,(1) 



The fishes of this genus, for a long time and very improperly united 

 with the Cobites, possess very peculiar characters; the cornea and 

 iris of their very prominent eyes, which are placed under a roof 

 formed on each side by the frontal, are divided into two portions by 

 transverse bands, so that the organ of sight has two pupils, and ap- 

 pears to be double, although it has but one crystalline and one vitre- 

 ous humour, and but one retina,(2) a peculiarity of which there is 

 no other example among vertebrated animals. In the next place we 

 find that the excretory canal of the organs of generation and of the 

 bladder, in the male, is situated in the anterior edge of the anal fin, 

 which is thick, long, and scaly; its extremity is perforated, and that 

 it serves for the purpose of copulation is indubitable. The female 

 is viviparous, and the young are considerably advanced in growth 

 at the moment of their birth. 



The body of these fishes is cylindrical and covered with stout 

 scales; there are five rays in the branchise; the head is flattened, the 

 snout truncated, and the mouth transversely cleft at its extremity; 

 both jaws are armed with small and crowded teeth; the intermaxil- 

 laries have no pedicle, and are suspended under the nasal bones 

 which. form the anterior edge of the snout. The greater part of the 

 pectorals is scaly, and there is a small dorsal on the tail, and nearer 

 to its extremity than the anal. The pharyngeals are large, and fur- 

 nished with very small globular teeth; the natatory bladder is very 

 large, and their intestine ample, but without caeca. 



But a single species is known; the Anableps tetrophtalmus, Bl., 

 361, Cobitis anableps, L. ; it inhabits the rivers of Guiana. 



PcECiLiAj Schn. 



The two jaws horizontally flattened, protractile, slightly cleft, and 

 furnished with a row of extremely small and slender teeth; top of 

 the head flat; large opercula; five rays in the branchiae; the body is 

 but little elongated, and the ventrals not far back; the dorsal above 

 the anal. Small viviparous fishes from the rivers of America.(3) 

 The 



(1) From ctvu/iKiTro), to raise the eyes, a name given by Artedi. 



(2) See Lacep., Mem. de I'lnstitut, torn. II, p. 372. 



(3) Pcecilia Schneideri, Val., or P. vivipara, Schn., 86, 2; — P. miiUilmeaia, 

 Lcsueur, Journ. Ac. Nat. Sc. of Philad., 1821, pi. 1; — P unimaculu, Val., App. 

 ITumb., Zool. Obs., IT, pi. li, f. 2; — P. sumtamensis, Id., lb., f, 1. 



