No. 393-] AUTODAX LUGUBRIS HALLOW. 695 
first place, the softness, delicacy, and constantly moist condi- 
tion of the skin of the entire body, and the abundant supply of 
blood vessels and capillaries within it, furnish the structural 
conditions necessary for respiration. In this connection the 
vascular supply to the toes deserves particular attention, 
A great blood sinus is present on each side, and near the end 
of each of these organs (Fig. 3). 
These lakes of blood, as they may be called, become partic- 
ularly conspicuous in animals that have been anesthetized 
with ether or chloroform, though they are easily seen by the 
aid of a hand lens in the normal living specimens. It is a 
reasonable supposition that we have here a not unimportant 
seat of respiration. No portion of the integument is better 
Fic. 3. 
calculated to make the most of what little moisture there may 
be in the animal’s surroundings, they being especially adapted 
to this end both as regards contact with moist bodies and area 
of surface exposed. The toes, in fact, may be considered to 
have assumed in a measure the function of external gills. 
How generally this vascular condition of the toes is among 
the amphibia we do not know. In two other species having 
much the same habits, at least as regards dwelling places, which 
we have examined, namely: Plethodon oregonensis and Batra- 
choseps attenuatus, practically the same conditions are found, 
while in Déemyctylus torosus, the habits of which are quite 
different, and in which lungs are present, no unusual degree of 
vascularity is found in the members. 
The toe-tips of Autodax are somewhat expanded (Fig. 3), 
and the animal has considerable power of clinging by means of 
them to vertical and overhanging surfaces. In this respect 
it resembles Hyla somewhat, and consequently a comparison 
between the two forms with respect to toe structure is suggested. 
