60 SYNOPSIS OF THE FAMILY HETEROPYGII. 



tion in the waters of the cave where it is more abundant than in other 

 places. The eggs were fully developed in these specimens, but no 

 embryos could be detected. The fish is probably viviparous, and 

 very likely gives birth to its young in October. 



Chologaster AGASSIZ, Amer. Jour. Sci., xvi, p. 135, 1853. 



Eyes in normal position and well developed. 



Head with small granulations on the surface of the skin. (No 

 papillary ridges.) 



Teeth minute, curved and arranged in rows on the intermaxillary 

 and inferior maxillary bones. None on the palatines in the adults. 

 (Of the four specimens examined, the two larger (C. cornutus) are 

 without palatine teeth, while the single specimen of C. Agassizii, 

 which is evidently a young fish, has a few minute teeth on the pala- 

 tine bones. In the smallest specimen of C. cornutus the mouth is 

 abnormal, the intermaxillaries being reduced to a small central portion 

 and there are consequently no teeth in the upper jaw, but the minute 

 teeth on the palatines are present.*) 



{Body without opercular papilla and papillary ridges on the sides.) 



Pyloric appendages two on each side. Stomach rounded and turned 

 slightly on the side. 



Ovary situated principally behind the stomach. 



Fins. Ventrals absent. Dorsal, 8 or 9. Anal, 8 or 9. Pectoral, 12. 

 Caudal, 28. 



This genus principally differs from Amblyopsis and Typhlichthj T s by 

 the presence of eyes, the absence of papillary ridges on the head and 

 body, by having two pyloric appendages on each side instead of 

 one, and by the posterior position of the ovary. It agrees with Typh- 

 lichthys in the absence of the ventrals, and the young further agree 

 by the presence of palatine teeth. 



*I believe this is one of those interesting cases where one set of organs, or one 

 portion of the animal structure, takes the place of another which from accident is 

 wanting, and that in all probability these palatine teeth, that under normal con- 

 ditions w r ould be cast off as the fish attained maturity, would have continued to 

 exist in this specimen and answer all the purposes of the intermaxillary teeth. 

 But that in this accidental continuance of these palatine teeth, from the mere 

 mechanical use forced upon them, we have the first stages of the development of 

 a distinct genus, to be characterized by permanent teeth on the palatines, and 

 reduced upper jaw bones, as many of the developmental school would argue, I do 

 not think will bear the test of facts observed. 



A not uncommon malformation of fishes consists in the entire or partial absence 

 of the maxillary or intermaxillary bones. I have specially noticed this among our 

 common fresh water trout (Salmo) and marine Conner or sea perch (Ctenolabrus) 

 but there have never been recorded allied genera with these characters, while 

 the malformed specimens are hardly numerous enough to give support to the the- 

 ory that such malformations are hereditary, and it is probable that each case was 

 caused by the non-development of the parts from special cause during embryonic 

 life, or by accident to the individual. 



