No. 387.] DESMOGNATHUS FUSCA. 245 
the same conditions. An examination of stomachs would, of 
course, settle this point; but I do not happen to have on hand 
at present any specimens which are known to have been kept 
for a long time in this manner. 
Advantages as Laboratory Animals. — The advantage sug- 
gested in the previous paragraph is an important one, being 
animals that may be easily kept in the laboratory during the 
winter without feeding or other attention. To collect them 
from the ¢errarium, lift up the stones exactly as when in 
the field, or else wait until 9 or 10 P.M., and bring a light 
suddenly upon them. They are nocturnal and at such times 
forsake their concealment and crawl about over the glass sides 
and roof. 
A second great advantage is that they may be collected out of 
doors all the year round, except during the time of deep snow, I 
have collected them with ease here in December and in March, 
thus leaving an interval of not more than 8-10 weeks during 
which they cannot readily be obtained. The eggs are peculiarly 
adapted to all sorts of experimentation ; they lack the black pig- 
ment of the frog’s egg, and thus give better results in staining. 
As their development is later in the year, they may be obtained 
after the eggs of frogs and toads have disappeared. The eggs 
of S. bilineatus develop readily when removed from the rock 
on which they are laid, if they are placed upon sand in a dish 
of water into which fresh water is constantly being introduced 
through a small pipe or glass tube. Those of D. fusca develop 
in the terrarium, and may be removed singly from the mass 
without disturbing the parent. It is highly probable that a 
mass of Desmognathus eggs would develop equally well when 
removed from the parent, if kept in the zerrarium under the 
usual conditions; but I have not yet had an opportunity to test 
this, and it is at least possible that necessary moisture and 
even warmth may be derived from the body of parent. 
