118 first Annual Report 
STUDIES IN LAGUNA ISOPODA 
BLANCHE E. STAFFORD 
In these and other studies, Asellus communis has been used more 
or less constantly as a basis of comparison, so that some drawings 
(Figures 65 and 66) of this species are presented in this paper. All 
of the other species were collected at Laguna Beach, California. 
The most robust and active Isopoda were found in the sand high 
up on the beach where they were driven out by the incoming water 
at high tide, and among the rocks at the high water mark. Of the 
former, the sand Isopod, Allomiscus perconvexrus, Was a common type, 
and Ligyda occidentalis was the characteristic representative in the 
latter surroundings. Under dead seaweed on the border of a salt 
marsh two forms were collected in fair abundance, one of which, 
Philoscia richardsonae, has been described in this report. At the 
lower level, under the rocks which the low tide uncovered, various 
forms of the family Idotheide were found; of these Idothea recti- 
linea was most numerous. Under these same rocks the species 
Cirolana harfordi was exceedingly plentiful. Hardly a rock was 
turned over that did not abound in this form. 
Occasional specimens were brought in from holdfasts which had 
drifted to shore from the kelp beds. These were generally very 
minute forms. From the sponges many curious tube-dwelling Iso- 
pods were collected. Rarely a parasitic form was discovered. The 
tide-pools furnished interesting members of the family Janiride. Of 
most of the latter and of the rarer species drawings and descriptions 
are not yet ready for publication. 
Asellus communis Say. 
Locality—F resh waters of Massachusetts. 
Body oblong and depressed, about three and a half times as long 
as wide, 17 mm. by 5 mm. 
Head measures 1.25 mm. in length and about 1 mm. in width at 
upper margin and 2 mm. at posterior margin. Hyes small, composite, 
and placed at the middle of lateral margins. First pair of antenne 
have basal article of peduncle broader than those distal to it. Second 
and third are narrow, third shorter than second; flagellum composed 
of fifteen articles. Second antenne have a peduncle of six articles; 
first very small, wider than long; second, third and fourth subequal ; 
fifth and sixth long and narrower; sixth longer than fifth; flagellum 
multi-articulate, composed of about sixty-two articles. Maxillipeds 
