2 The Blind Cave Fishes and their Allies. [January, 



ation did not bring about the atrophy of their eyes, the develop- 

 ment of their special organs of sense, or the bleaching of their 

 skins. 



The discussion seems not to have been carried further ; and I 

 now revive the subject because the study of a new species closely 

 allied to the blind fishes, which has recently been discovered in 

 Illinois, enables me to contribute a few facts which throw addi- 

 tional light upon it. 



In the papers cited, it is argued, in brief, that the conclusions 

 as to adaptation based upon the absence of functional eyes and 

 the extraordinary development of tactile organs in Amblyopsis 

 and Typhlichthys are negatived by the fact that in Chologaster, an 

 equally subterranean genus, tactile organs are wanting, and eyes 

 are fully developed. If genera without eyes, and another genus 

 with them, are found living under the same conditions, the infer- 

 ence is obvious that the conditions cannot have caused this dif- 



The possible rejoinder that Chologaster may still retain its eyes 

 because it has had a shorter subterranean history, and has not yet 

 become so thoroughly adapted to cave life as its predecessors, is 

 forestalled by the argument that we have no right to assume that 

 Chologaster is a later inhabitant of underground retreats than the 

 blind fishes, until at least one specimen of the former has been 

 found in the outer waters in the vicinity of the caves. The same 

 reasoning is applied to the difference of color — Amblyopsis being 

 colorless and Chologaster brown. 



On page 232 of the Naturalist for March, 1881, I briefly 

 described a single specimen of Chologaster obtained by Mr. F. 

 S. Earie from a spring in Southern Illinois; but did not under- 

 take to decide, from a single example, whether it belonged to a 

 distinct species or not. Seven additional specimens obtained by 

 the same gentleman from the same place, agree so closely with 

 the one.previously found that it is evident that all belong to one 

 species, and I have no longer any doubt that this is distinct from 

 the two previously described. 1 



^Chologaster papilli/i-rus, n. s. The head is broad and flat, contained three and a-half 

 in the length of the head, and is placed above and behind the tip of" the maxilla- 



