ORIGIN OF THE BLIND FISHES. 47 



Journal," and were it not tbat the article has been reprinted in the 

 " Annals and Magazine of Natural History," I should not criticise 

 the statement made in an off-hand letter for publication in a news- 

 paper ; for with Prof. Cope's knowledge of fishes it could simply be 

 a hasty thought which he put on paper, when he suggests that it is 

 because the Cyprinodontes have a mouth directed upwards and 

 are surface feeders that they were better adapted to a subterranean 

 life than other fishes, and hence maintained an existence, while 

 other species, which he supposes were introduced into the subter- 

 ranean streams at the same time, died out. 



If the fishes of the subterranean streams came from adjoining 

 rivers, why were not many of the Percoids, Cyprinoids and other 

 forms, that are as essentially surface feeders as the Cyprinodon- 

 tes (many of the latter are purely "mud feeders"), as capable of 

 maintaining an existence in the subterranean waters as any species 

 of the latter ? Neither is it necessary for us to assume that the 

 structure of the fish should be adapted to feeding on the surface, 

 for not only have we in the blind cat fish, described by Prof. 

 Cope himself, from the subterranean stream in Pennsylvania, 

 an example of a fish belonging to an entirely different family of 

 bottom feeders, thriving under subterranean conditions, but the 

 blind fishes of the Cuban caves are of the great group of cod fishes 

 which are, with hardly an exception, bottom feeders. The fact 

 that the food of the blind fishes of the Mammoth Cave consists in 

 great part of the cray fish found in the waters of the cave, as 

 shown by the contents of several stomachs I have examined, and 

 also that one blind fish at least made a good meal of another fish, 

 as already mentioned, shows that the} T are not content with simply 

 waiting for what is brought to them on the surface of the water, 

 and that they are probably as much bottom as surface feeders. 



Again, in regard to the sense of sight, why is it necessary to 

 assume that because fishes are living in streams where there is lit- 

 tle or no light, that it is the cause of the non development of 

 the eye and the development of other parts and organs? If this 

 be the cause, how is it that the Chologaster from the well in Ten- 

 nessee, or the "mud fish" of the Mammoth Cave are found with 

 eyes? Why should not the same cause make them blind if it made 

 the Amblyopsis and Typhlichthys blind? Is not the fact, pointed 

 out by Prof. Wyman, that the optic lobes are as well developed in 

 Amblyopsis as in allied fishes with perfect eyes, and, I may add, 



