472 TUBE-BLADDERED GROUP. 



The Blind-Fish,— Family Ambl topside. 



The celebrated blind-fish {Amblyopsis spelcea) from the Mammoth Cave in 

 Kentucky, the Wyandotte Cave in Indiana, and the subterranean streams which 

 appear to connect the waters of the two, is generally regarded as the typical repre- 

 sentative of a family closely allied to the last. This fish, which does not exceed 5 

 inches in length, and breeds viviparously, closely resembles the genus Cyprinodon 

 in that certain specimens (which have unnecessarily been separated as Typhlichthys) 

 lack the pelvic pair of fins. All traces of external eyes are wanting, and the skin is 

 totally devoid of colour. In order to enable the creature to find its way about in 

 the dark subterranean waters of the limestone rocks of the Central United States, 

 its head is provided with a large supply of organs of touch, arranged in a series of 

 transverse ridges on each side ; while its sense of hearing is also stated to be very 

 highly developed. Professor Cope writes that if these fish " 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 preserved, for 



KENTUCKY BLIND-FISH (liat. size). 



they are unconscious of the presence of an enemy except through the medium of 

 hearing. This sense is, however, evidently very acute, for at any noise they turn 

 suddenly downwards and hide beneath stones, etc., on the bottom. They must 

 take much of their food near the surface, as the life of the depths is apparently 

 very sparse. This habit is rendered easy by the structure of the fish, for the 

 mouth is directed partly upwards, and the head is very flat above, thus allowing 

 the mouth to be at the surface. It thus takes food with less difficulty than other 

 surface-feeders, as the perch, where the mouth is terminal or even inferior; for 

 these require a definite effort to elevate the mouth to the object floating on the 

 surface." Nearly allied to that variety of the blind-fish in which pelvic fins are 

 absent is a small fish known as Ghologaster, in which small external eyes are retained, 

 and the body is coloured ; the front of the head being provided with a pair of horn- 

 like appendages. These small fish were first known from three examples taken in 

 the ditches of the South Carolina rice-fields, but a fourth specimen was captured in 

 a well in Tennessee in the year 1854. The retention of the eyes and their dark 

 colour indicates that these fishes have taken to a partially subterranean life more 

 recently than the blind-fish. 



