1889.] ^^otcs on the Habits of Some Aniblystomas. 605 
organs of adhesion of the frog are said to do. In microscopic 
sections the epidermal cells near the tip of the organ appear each to 
project into a point, so that the whole surface is roughened some- 
what. Since all objects in the water soon become covered with a 
thin layer of slime, the holders will adhere to this with sufficient 
force to suspend a little creature which is of nearly the same 
specific gravity as the water. When they are put into a clean 
glass or tin vessel, it is with great difficulty that they can succeed 
in attaching thcmscK cs to the perpendicular side. After making 
many unsuccessful efforts they sink to the bottom seemingly ex- 
hausted, and lie quite as often on their sides as on their bellies. 
When the holders have been lost, I have observed the larvae to 
suspend themselves to the walls by means of their toes, or by a 
While they are adhering to objects by means of the holders 
one may, under a lens, and with the point of a fine forceps, loose 
one holder and allow the tadpole to hang by the other alone. 
One max- tlien touch the forcqxs to the adhering holder, and 
succrr.l in (lr,i-i;ing the little animal hither and thither through 
Larv.r of the Kngth of 15 mm. liad their intestines filled with 
the remains of small auinials. These consisted mostly of ento- 
mostracous crustaceans, such a< J\7/^Ii>iiidu, ^jr^/J, and the like ; 
but there were also found portions of the young of Crangonyx 
and Astilus, and of the larva of some beetle. The ponds which 
harbor these amphibians literally swarm with minute animal life, 
and the tadpoles are active, hungry, and fierce. 
When the tadpoles have become about 25 mm. long, they may 
occasionally be seen to come to the surface for air. This shows 
that the lungs are becoming functional. A bubble of air is ex- 
pelled by the mouth just as, or before, the tadpole reaches the 
surface; a portion of fresh air is probably inhaled ; and the tad- 
pole hastens to the bottom, as if alarmed at having exposed itself 
The changes from this time on until near the time of metamor- 
phoi^s consist principally in increase in size and further develop- 
ment of the limbs. A tadpole two inches long and full-grown 
may be briefly described. Those who are familiar with figures 
