230 University of California Publications in Zoology (Vou. 23 
as I know, on rocky shores. This preference for a sandy bottom is correlated 
with certain structural peculiarities and a group of habits which may be men- 
tioned here on account of their bearing on the methods of fishing. Observation 
of the crab where accessible in shallow water and of the young in aquaria furnish 
the following facts: The crabs may often be seen moving quietly along over the 
Cancer magister, reduced (after R. Rathbun). 
Fig. 138. 
