VOL. I. | The Point Loma Blind Fish. 69 
The skin, and especially that of the head, has become highly 
sensitized. The skin of the snout is variously folded and puckered, 
and well supplied with nerves; the nares are situated at the end of a 
fleshy protuberance which projects well forward, just over the 
mouth. At the chin are various short tentacles and a row of pa- 
pill, which very probably bear sensory hairs similar to those rep- 
resented in 18 and 19, extends along each ramus of the lower jaw, 
and along the margin of the lower limb of the preopercle. The eye 
is, however, the part most seriously affected. In the young, fig. 7, 
it is quite evident, and is apparently functional. Objects thrust in 
front of them are always perceived, but the field of vision is quite 
limited. With age the skin over the eyes thickens, and they are 
scarcely evident externally. As far as I could determine they do 
not see at this time, and certainly detect their food chiefly, if not 
altogether, by the sense of touch. A hungry individual will swim 
over meats, fish or a mussel, etc., intended for its food without per- 
ceiving it by sight or smell, but as soon as it comes in contact with 
any portion of the skin, especially of the head region, the sluggish 
movements are instantaneously transformed, and a stroke of the 
fins brings the mouth immediately in position for operations. 
I have not been able to raise the fishes from the egg. The 
youngest individual ever seen is represented in fig. 7. In this 
specimen the membranes of the fins were thin, the color cells were 
well formed and arranged not unlike those of the young Gillich- 
thys, fig. 15. The movements were similar to those of the other 
gobies, and not at all sluggish like those of the adult. Their 
favorite position is standing or sitting, one with the broad pectorals 
extending out at right angles to the body. In this position the fish 
can, with a sudden stroke of its pectorals, move quickly and rap- 
idly. In the old the fins are thick and smaller in proportion, and 
all the vivacity seems to have disappeared. The color has degen- 
erated, or at least not developed in proportion to the growth of the 
fish. 
The minute structure of the eye was not examined on account 
of the entire lack of the proper facilities for sectioning, etc. 
The eye and optic nerve have been isolated by treatment 
with 20 per cent. nitric acid, and by simple dissection of alcoholic 
specimens. The lens is large in proportion to the size of the eye, 
which does not materially differ in size in the smallest and largest — 
