en 
PHRYXUS HYNDMANNI. 24d 
head. The legs are very robust, but folded so as not to 
extend beyond the sides of the body. The tail is com- 
posed of six joints, gradually diminishing in width, the 
last being very small, nearly oval, the tip pointed, and 
with a minute seta on each side beyond the middle. 
Dr. Fritz Miiller, in a letter to us dated in 1864, 
observes, that ‘‘ One of the most interesting animals of 
this family is a Bopyrus living on Pagurus, in which the 
dorsal surface of the parasite is directed towards the 
Pagurus (I therefore named it B. resupinatus). The origin 
of this curious manner of attachment is the following :— 
The larva of Bopyrus fixes itself to the Sacculina purpurea, 
living on the same Pagurus, and takes its nourishment 
from the roots of the parasite. After the death of 
the Sacculina, to whose ventral surface the Bopyrus was 
fixed, the latter probably cannot change its position, and 
remains with its dorsal surface facing the Pagurus.” 
