Pomona College, Claremont, California 37 
given under the separate species will show that many of the individuals studied, and 
practically all of these in which the mouth was enlarging, containgg ete Beste, It 
seems hardly necessary to say in this connection that the absorpti  ,must make 
possible this period of fasting. 
It must take some little time for the food to pass through the long alimentary 
canal of the larva, since it was quite noticeable that in many of those examined in 
which the mouth plates had recently been shed, the caudal portion still contained the 
mud and other contents typical of the larva and which had probably been taken into 
the body when the mouth plates were still in place. 
The length of the body without considering the tail, remains almost unchanged 
during transformation, but the rotund aspect of the tadpole gives way to the flatter 
and more angular one of the young frog. The appearance of the front legs, the left 
one coming out through the spiracle and the right one breaking through the skin, 
as well as the shrinking of the tail are further indications of the progress made in 
transformation. Usually the tail is almost gone before feeding as a carnivor begins. 
It is to be noticed that in the data given for the bullfrog almost every trans- 
forming individual is reported as having swallowed some of its own cast epidermis. 
This is true to a lesser degree of the other species, probably because the much smaller 
size of such species as the tree-toad and the toad makes the rcognition of epidermis 
in the alimentary tract of preserved specimens more uncertain. The frequent occur- 
rence, one might say almost universal occurrence, of epidermis in transforming 
individuals must mean frequent moulting. Doubtless this is true, especially of the 
tail, which shrinks rapidly and might naturally shed its epidermis. That the shedding 
of the skin takes place in the water is evidenced by the threads of Spirogyra and 
Zygnema often wrapped up in it as if during seizing and swallowing. 
The discussion of transformation may be concluded, then, by saying that it is 
accompanied by a period of fasting during which time, in all eight species, the food- 
getting and food-assimilating apparatus is rebuilt and changed from one suitable 
to a form largely herbivorous and at*least feeding only on dead animal material, 
to one which will permit of the predaceous and carnivorous habits of a frog or toad. 
PRESENTATION OF DATA FOR THE SPECIMENS EXAMINED 
In the following pages lists are given of the specimens dissected with data show- 
ing the degree of transformation and the contents of the alimentary canal. The 
word “stomach-content” is not sufhicent here; for in many cases the stomach was 
almost empty while the large intestine contained large amounts of food; in the case 
of insects, passage through the digestive tract in this way had not sufficiently changed 
many specimens to make it impossible to identify them to family at least. In the 
data given under each species, “No.” refers to the number of the specimen, “Body” 
to the length in millimeters, measuring from the tip of the head to the base of the 
tail; “Tail” to the length of the tail in millimeters, “Mouth” to the condition of the 
mouth, whether that of the tadpole with the horny plates or with these shed, or with 
the mouth enlarged; “Ali. Can.” to the length in millimeters and to the condition 
of the alimentary canal; “Fore Legs” to the presence or absence of the front legs; 
“Lot” to the lot to which the particular specimen belonged, and “Food” to the 
material found in the digestive tract. 
