JERA ALBIFRONS. 319 
J. alhifrons probably occurs all round our coasts. We 
have it recorded on the Devonshire and other coasts, 
among sea-weeds and under stones, in many parts of the 
British islands. It was found especially abundant in 
crevices of rocks at half-tide near Falmouth, by Mr. W. P. 
Cocks, and we have taken it abundantly beneath and 
generally attached to the under surface of stones between 
tide-marks in. Plymouth Harbour, the flat surface of the 
body enabling the animal to ensconce itself in very slight 
crevices. The late Dr. Johnston also forwarded it to us 
from the Berwickshire coast. 
