94 ZOOLOGY 



colorless body and eyes that are rudimentary or concealed 

 beneath the skin. Their behavior has been thus described: 

 " If these Amblyopses be not alarmed, they come to the surface 

 to feed, and swim in full sight, like white aquatic ghosts. 

 They are then easilj' taken liy the hand or net, if perfect 

 silence is preserved, for they are unconscious of an enemy 

 except through the medium of hearing ; this sense, however, 

 is evidently very acute, for at any noise they turn suddenly 

 downwards, and hide beneath stones, etc., on the bottom " 

 (Cope). There is, however, reason for thinldng that their 



Fig. 95a. — Amblyopsis, the cave blind-fi.sh, from Blatchley : "Glean- 

 ings from Nature." 



tactile sense is acute, for the head is provided mth numerous 

 tactile warts. These fishes spend their whole life in the caves, 

 never seeing the light of day, and the question arises, whence 

 did they come, how did they get into the caves, and why are 

 they blind? As to the first question it is certain that they must 

 have come from surface streams, because all their numerous 

 close relatives still live above ground. To learn how the blind 

 fishes got into caves we must study their relatives above ground, 

 and we shall find that some inhabit dense swamps and others 

 occur under stones in springs. The whole family of Ambly- 

 opsidaj are light-shunners and, being such, a cave has offered 

 the best possible place for one of this family. As to why they 

 are blind it appears that it is not due to their cave life, since 

 some of the relatives above ground in regions where there are 



