SPHEROMA, 4O] 
ISOPODA. SPH #ROMIDA. 
NORMALIA, 
Genus—SPHAXROMA. — (Latreille.) 
Generic character. Animal capable of rolling itself into a 
ball. Cephalon small, with the eves dorsally situated at the 
posterior angles. Antenne small. Pereiou much broader than 
the cephalon, with seven distinct segments, having the first 
laterally anteriorly produced, so as to reach the anterior mar- 
gin of the cephalon. Coxe small. Pleon having all the 
segments fused together, with the posterior margin entire. 
Uropoda consisting of a peduncle that is posteriorly produced 
into a long, flat, oval process, carrying a single ramus which 
is articulated near the base. 
THE genus, as originally designed by Latreille, was 
co-extensive with the present family (with the ex- 
clusion of the remarkable genera, Circeis (Australian), 
Amphoroidea (Chilian), Cassidina and Ancinus (both of 
unknown locality), four genera recently established by 
Professor Milne Edwards. Dr. Leach, however, in his 
Memoir in the ‘ Dictionnaire des Sciences Naturelles,”’ 
divided it into seven genera, most of which have sub- 
sequently been adopted by Latreille and other carcino- 
logists; the typical genus Spheroma comprising most 
of those species which are able to roll themselves up 
into a ball, at which time the lateral appendages of the 
tail are not visible. 
These animals are of small size, rarely reaching to the 
length of half an inch, 
VOL. Il. DD 
