MUSEUM OF COMPARATIVE ZOOLOGY. 95 
I have dwelt thus at length on this question of color in other blind 
fishes because Eigenmann (’90, p. 68) has said with reference to the 
color of Typhlogobius that “in its pink color and general appearance 
this fish much resembles the blind fishes inhabiting the caves of South- 
ern Indiana.” I suppose this to refer to Amblyopsis, as there is not to 
my knowledge any other blind fish known from the caves of this region. 
Whether Eigenmann’s statement about the color of the Indiana fishes 
is to be taken as opposed to those quoted from other writers or not, the 
most significant fact for our purpose is that there is certainly no such 
degree of vascularity in the integument of Amblyopsis as is found in 
Typhlogobius. I have had opportunity to examine a well preserved alco- 
holic specimen of this species, obtained by Professor Mark from Professor 
Putnam. I prepared fragments of the skin in the same way that had been 
employed in studying that of Typhlogobius, and found the blood-vessels 
here to be even less abundant than in the integument of the Clevelandia 
and Lepidogobius that I have examined. 
The most serious objection, I think, to the supposed respiratory func- 
tion of the skin lies in the thickness and density of the epidermis, and 
the fact that the entire surface is thickly beset with the slime-secreting 
cells (see Figs. 9, 10, and 17). I do not believe, however, that the 
epidermis here would offer greater resistance to the interchange of gases 
than would that of the frog ; certainly, as regards the integumentary 
glands and their products, the frog’s skin can hardly be more favorably 
constructed for a respiratory function than that of the blind fish. When 
we remember the dense cuticular layer that covers the entire surface of 
such animals as the earth-worm, where all the respiration must be carried 
on through the body wall, this obstacle does not seem so great. More- 
over, in Cobitis fossils, where intestinal respiration is well known to take 
place to a considerable extent, although it was long supposed that no epi- 
thelium was present in the region of the intestine, — in which from the 
richness of the blood-vessels the respiration is supposed to be carried 
on, — Lorent has shown not only that there is an epithelium present, but 
that it consists of two layers, a superficial layer of flat polyhedral cells, 
and beneath this a layer of stratified cylindrical epithelial cells, among 
which are scattered beaker cells (Wiedersheim, ’86, p. 572). 
Of course the ultimate test of my theory must be made by physio- 
logical experimentation, and I hope to be able to do this before long. I 
annot suppose gill respiration to be to any great extent supplanted by 
integumentary respiration, since the gills appear to be normally devel- 
oped. It is necessary, then, to suppose that the latter method supple- 
