472 
TUBE-BLADDERED GROUP. 
The Blind-Fish,— Family Ambl yopsidaj. 
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 Typlilichthys ) 
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.” Neai’ly allied to that variety of the blind-fish in which pelvic fins are 
absent is a small fish known as Chologaster, 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 
recentfy than the blind-fish. 
