46 
ORIGIN OF THE BLIND FISHES. 
b^yopsis and Typliliohtli3^s by the presence of eyes, the absence of 
papiilaiy ridges on the head and body, and b}^ the longer intestine 
and double the number of pyloric appendages, as well as by the 
position of the ovary ; and agrees with Typhlichthys by the ab- 
sence of ventral fins. Amblyopsis and Typhlichthys are near]}'- 
colorless, while Ohologaster Agassizii is of a brownish color similar 
to many of the minnows, and C. cornutas is brownish yellow, with 
dark, longitudinal bands. 
Among the most interesting points in the history of this genus 
is the fact of its occurring in two widely ditferent localities, C. 
Agassizii having been found in a well, in the same vicinity (proba- 
bly in the same wmll) with a specimen of Typhlichthys, and 
undoubtedly belonging to the same subterranean fauna west of the 
Appalachian ridge, while C. cornutus belongs to the southern coast 
fauna of the eastern side of that mountain chain, and is thus far 
the only species of the family known beyond the limits of the great 
subterranean region of the United States. 
Having now given an outline of the structure, habits and distri- 
bution of the four species belonging to the family, and recapitu- 
lated the known facts, we are better able to consider the bearings 
of the peculiar adaptation of the' blind fishes, in the Mammoth 
and other caves, to the circumstances under w'hich they exist. 
Prof. Cope in stating, in his account of the blind fish of the 
AVyandotte Cave, “that the projecting under jaw and upward di- 
rection of the mouth renders it easy for the fish to feed at the sur- 
face of the water, where it must obtain much of its food,” suggests 
that : — 
“This structure also probably explains the fact of its being the 
sole representative of the fishes in subterranean waters. No doubt 
many other forms were carried into the caverns since the waters 
first found their way there, but most of them were like those of 
our present rivers, deep water or bottom feeders. Such fishes 
wmuld starve in a cave river, where much of the food is carried to 
them on the surface of the stream The shore minnows 
are their nearest allies, and many of them have the upturned 
mouth and fiat head Fishes of this, or a similar family, 
enclosed in subterranean waters ages ago, would be more likely to 
live than those of the other, and the darkness would be very apt 
to be the cause of the atrophy of the organs of sight seen in the 
Amblyopsis.” 
This suggestion was undoubtedly hastily made by Prof. Cojie 
when writing the letter which was printed in the “Indianapolis 
