1894.] Subterranean Fauna of North America. 737 
“ Indeed, one can hardly doubt that this astonishing devel- 
opment of the eye has been accomplished by the influence of 
light as has also the pigmentation of the skin, the reddish- 
white ground color of which appears thickly studded with 
very small brownish-gray points mixed with detached white 
ones, over the upper surface of the head and over the back 
down over the sides of the yellowish abdomen. Even on the 
edge of the fins (Flossensaum) the pigment is found. On the 
other hand there is a whitish spot over the snout as is likewise 
the case in the adult creatures which have been colored by the 
light. Both the under surface of the head and the entire ab- 
domen are shown free from pigment like the limbs. 
“ T cannot specify very exactly as to when the digmentation 
of the skin begins, but, in any case, it is very early and often 
earlier that the first beginning of the eyes can be discovered. 
The latter occurs toward the end of the twelfth week, at which 
time a thin, light gray line, which still appears overgrown, 
may be perceived, forming a half circle open underneath. 
Then while this line subsequently becomes clearer and darker 
and its ends grow further under and towards each other, there 
also takes place simultaneously a progression of the pigment 
larger towards the middle point, and the circle finally seems 
closed and filled up to the narrow slit mentioned above, which 
proceeds from the lower circumference and penetrates to the 
middle of the eye.” (p. 570, 571.) 
But the most striking discovery bearing on this subject is 
that of the condition of the eyes in the embryo and young com- 
pared with the adult of the blind goby of San Diego. 
In his essay on the Fishes of San Diego, Professor Eigen- 
mann briefly refers to and gives four figures (Pl. XXIV) of 
the embryo of Typhlogobius, Mr. C. L. Bragg having been for- 
tunate enough to discover the egg in the summer of 1891. 
“The eyes.develop normally, and those of Fig. 4 differ in no 
way from the eyes of other fish embryos.” In this case, then; 
we have the simplest and clearest possible proof of the descent 
of this blind fish from individuals with eyes as perfect as those 
of its congeners. 
We have been permitted by the Director of the United 
States National Museum to reproduce Professor Eigenmann’s - 
