BULLETIN THE 
OF 
The Integumentary Sense Pupille. 
1. These have been considered only so far as pertains to the question 
whether they have been developed to compensate the rudimentary con- 
dition of the eyes ; and it is concluded that such is not the case. 
2. The facts that lead to this conclusion are the presence in several 
closely related genera — four at least — of the tactile papille with the 
same distribution as those of Typhlogobius, and in addition to this, on 
parts of the body where they are not found at all in Typhlogobius, ex- 
cepting in the smallest specimens ; and that the papille that are present 
in Typhlogobius are not more highly developed than those of correspond- 
ing regions in related genera. 
3. In comparing the several species of blind fishes with a view to de- 
termining under what conditions the tactile sense does become developed 
to compensate the loss of sight, it is concluded that, while the greater 
activity of the cave blind fishes might explain their more highly developed 
tactile papille, this cannot be affirmed as a general law, since other 
blind fishes (as some at least of the deep-sea forms and probably also 
the blind Silurids) are without tactile papille, while we have no rea- 
son to suppose them less active than the cave fishes. It is necessary to 
have more knowledge than is yet possessed of the mode of life of the 
various blind forms before this question can be fully answered. 
The Integument. 
1. This structure has been studied with reference to the pigment con- 
tained in it, and the pink color of the living fishes. 
2. Very nearly if not fully as much pigment is present in the largest 
as in the smallest specimens, the lighter color of the former being due 
to the obscuration of the pigment by a thickening of the sub-epidermal 
tissue between the pigment and the epidermis. 
3. The pink color of the living animals is due, in great part at least, 
to a highly abnormal development of blood-vessels in the sub-epidermal 
portion of the integument. 
4. So far as it has been possible to determine, this vascularity of the 
skin is unique in this fish. 
5. The most probable explanation found of this condition is that it is 
for the purpose of cutaneous respiration, 
UNIVERSITY OF CALIFORNIA, BERKELEY, 
July 4, 1892. 
