234 BULLETIN OF THE 



winter we can only imagine. Hiding places are so numerous and exten- 

 sive as to suggest the possibility of the evolution of blind forms without 

 the caves. The great essential would be the disposition to avoid the 

 light, opportunities existing everywhere ; the surroundings then would 

 bring the organization into harmony with their demands, sooner or later 

 as the creature was more or less plastic and yielding ; disuse of the sense 

 of sight being followed by its loss and atrophy of its special organ. 

 Development of sightless forms in the holes and burrows of the banks, 

 or in the mud of the bottom of the river, would here follow a similar 

 course to that gone through at great depths iu lake or ocean. 



Crooked streams are not so impassable as one might suppose, even 

 to floating objects, insects, mollusks, etc. A twig or leaf dropped into 

 the current on the inside of the upper arm of a horseshoe curve in 

 a stream is carried near to the opposite shore before it leaves the bend, 

 and, especially if favored by the wind, often is carried completely across. 

 The passage is much easier to animals that swim, however feebly. 

 Taking everything into the account, it does not appear to be at all 

 necessary to credit Typhlichthys subterraneus from Kentucky, Tennessee, 

 and Missouri with more than a single point of origin. The same may 

 be said of Amblyopsis spelceus of Kentucky and Indiana, and of the blind 

 crayfish of the same States. 



In an article entitled " Life in the Wyandot Cave," Ann. Mag. Nat. 

 Hist., Ser. 4, VIII., 1871, p. 368, Professor Cope makes this statement 

 concerning Amblyopsis : " 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 easily taken by the hand or net, if perfect silence is pre- 

 served ; for they are unconscious of the presence of an enemy, except 

 through the medium of hearing. This sense, however, is evidently very 

 acute ; for at any noise they turn suddenly downward and hide beneath 

 stones, etc. on the bottom." The statement is repeated in Amer. Nat., 

 1872, p. 409. Such a development of this sense, in recesses where we 

 are accustomed to think any sounds other than those made by the rip- 

 pling or dripping water are almost unknown, is not what one would have 

 expected. Having this in mind, I wrote to Miss Hoppin asking her to 

 make experiments on Typhlichthys, and to determine what she could in 

 regard to hearing, feeding habits, etc. The quotations here given are 

 from her replies. 



" For about two weeks I have been watching a fish taken from a well. I 

 gave him considerable water, changed once a day, and kept in an uninhabited 

 place subject to as few changes of temperature as possible. He seems perfectly 



