230 
Amblyopsidee, whether blind or seeing, if kept in an aquarium dark- 
ened at one end seek the dark. They were not swept into the caves, but 
entered them deliberately and avoided coming out into the light. In short, 
they were able to establish themselves in caves because they were able to 
do without light, having simplified eyes and highly developed sense organs; 
they do not possess highly developed sense organs and degenerate eyes 
because they were accidentally swept into caves. The further degenera- 
tion of the eye in total darkness and the greater perfection of the sense 
organs are separate questions. 
Tur AMBLYOPSIDAE AND Eyes or BLIND FisHes. By C. H. E1GENMANN. 
[Abstract. } 
Our knowledge of the eyes of the North American blind fishes 
is based on the result of gross dissections of Amblyopsis made by 
Wyman before 1872 and on a brief account of the eyes of two specimens 
of Typhlichthys by Kohl (1895). Kohl's specimens, coming from Missouri, 
were made to do duty for the blind fishes in general. His paper is poor in 
the material examined and entirely perverse in his interpretation of the 
conditions observed. He does not state the habitat of his specimens. A 
comparative study of the eyes of Typhlichthys from Mammoth Cave and 
from Missouri led me to suspect that his specimens came from Missouri, 
and in this I found I was correct. The Typhlichthys inhabiting the under- 
ground streams of Missouri is very different from that inhabiting Mam- 
moth Cave, and, unfortunately for the generalizations of Kohl, the differ- 
ence lies in the structure of the eye. 
The North American blind fishes are especially favorable for the 
study of degeneration and of many questions bearing on the origin of 
cave faunas because they have seeing representatives living in the open 
and others living with them in the caves. 
The members of the Amblyopsidze and their distribution is as follows: 
Chologaster cornutus. Abundant in the lowland swamps of South- 
ern States. 
Chologaster agassizii. Subterranean streams in Tennessee and Ken- 
tucky and probably identical with the next. 
