542 ANTHON. [VoL. XIX. 
Il. Hapitat AND MopE oF LIFE. 
Ctenophora larvee are somewhat gregarious in habit and 
are usually found massed in runways, as it were, in much 
decayed cottonwood or alder logs. They are rarely found 
in other logs and never in such great numbers. Where a 
single specimen is found a. half hundred or more will com- 
monly be found in the same log, though sometimes only a 
few will be secured. As the larve require moisture, they 
are usually found in the soft, punky wood along the lake 
shores. The numerous specimens used in this study were all 
secured from the small strip of the Lake Washington shore 
on the university campus. The larva probably obtains its 
food supply from the bacterial life found in this spongy 
wood; as when many of them are kept for some time in 
the same material they gradually absorb the plentiful adipose 
tissue, which apparently furnishes a reserve food supply. 
Numerous protozoan parasites are frequently found in be- 
tween the cells of the alimentary canal, especially in the 
proventricular czca. 
III. DEscrRIPTION OF THE LARVA. 
The Ctenophora larva (Fig. 1) is cylindrical, tapering 
somewhat towards the hinder end, and is bluntly rounded in 
front, especially when the head is much retracted. The larva 
is from three-quarters of an inch to a trifle over an inch in 
length. There are no external appendages or protuberances, 
but the animal is found covered with numerous fine hairs, 
extending backwards. When the larva is held to the light, 
these cause it to appear yellow on the edges. The larva 
moves quite freely by vermiform movements, and these are 
possibly facilitated by the presence of the hairs. The body 
proper consists of eleven segments, which, with the exception 
of the first and last, are not clearly marked off. Most of 
these segments are subdivided into annuli, but as the number 
of annuli varies in different specimens, and even in the dorsal 
and ventral portions of the same individual, their morpholog- 
