234 REPORT OF STATE GEOLOGIST. 



** Upper margin of the mouth formed posteriorly by the maxillaries. 

 t No lateral line ; mouth large. dmbridce, p. 238. 



ft Lateral line present ; mouth large, Ludidoi, p. 239. 



Family AMBLYOPSIDiE. 



Small fishes, with large flattened heads. Mouth large ; the non-pro- 

 tractile premaxillaries forming the whole of the upper margin. Head 

 without scales, furnished with papillary ridges. Scales of the body 

 cycloid and irregularly arranged. Vent at the throat. 



Genera of AMBLYOPSID^. 



a. Ventrals present, small ; eyes blind ; body colorless. 



Amblyopsis, p. 234. 

 aa. Ventrals wanting. 



b. Blind, colorless fishes. Typhlichthys, p. 234. 



bb. Colored fishes with developed eyes. Chologaster, p. 234. 



Genus AMBLYOPSIS DeKay. 



Eyes concealed beneath the skin. Head without scales and crossed 

 by tactile ridges. Gill-membranes connected with the isthmus. Ventral 

 rays very small, situated near the anal fin. A single species known. 



Amblyopsis spel/eus DeKay. 



Mammoth* Cave Blind-fish. 



Jordan and Gilbert, 1882, 8, 324. 



Body rather long, heavy forward. Head long and flat. Depth in the 

 length about four and one-half times. Head in length three times. 

 Mouth large and directed upward. Head crossed by tactile ridges. 

 Dorsal rays nine ; anal eight. Colorless. Length five inches or less. 



Kentucky and Indiana in caves and underground streams. Common 

 in Wyandotte and neighboring caves.* 



•'■'The genus Tuphlichthys differs from Amblyopsis in liaving the ventral fins wholly want- 

 ing. Only a single si)ecies is known, T. subterraneus. It has been found in caves and wells in 

 Kentucky, Tennessee and Alabama, and is not unlikely to occur in the caves and under- 

 ground streams of the region in Indiana occupied by the subcarboniferous limestone. It 

 may be distinguished from A. spelxtis by the absence of ventrals. Since these are quite 

 small in the latter species, a close examination is necessary. 



The genus Chologaster may also be represented in the fauna of Indiana, although of this 

 there is yet no evidence. The genus diifers from the two preceding in having well devel- 

 oped eyes and in having a pigmented skin like ordinary fishes. There are no ventrals. 



C.agnssizii occurs in subterranean streams in Kentucky. The color is a uniform light 

 brown. The eye is large. The length is about an inch and a quarter. 



G. pap ill if ems has been described by Forbes from Union County, Illinois. It reaches a 

 length of only an inch. It is of a yellowish brown color, darker above. The sides have 

 three dark streaks. The eye is small, six times in length of head. 



