120 A HISTORY OF RECENT CRUSTACEA 
yellowish-brown, but this is little or no guide to what its 
colour may have been when living. ‘The specific names in 
this genus ought to have either masculine or else neuter 
terminations, but many naturalists seem to suppose that 
any generic name ending in -a is a feminine form, which 
is far from being the fact. 
In this family the genus Libinia, Leach, 1815, contains 
several species, and Mithraw (Leach), Latreille, 1817, a 
very large group. Of Inbinia emarginata, Leach, Miss 
Mary Rathbun, in her recent revision of the Periceride, 
says that in Long Island Sound occasionally this species by 
its numbers ‘so interferes with the steam oyster dredgers 
that work is abandoned until the crabs (which are known 
to the oystermen as “ spiders”) have passed over.’ 
Legion 2.—Parthenopinea. 
The basal (or true second) joint of the second antennze 
is very small and embedded with the next joint in the 
narrow gap between the ‘front’ and the inner orbital 
angle, the infraocular space being mainly occupied by the 
inferior wall of the orbit. 
Family 4.—Parthenopide. 
The eyes are usually retractile within the small circular 
and well-defined orbits; the lower wall of the orbit is con- 
tinued to within a very short distance of the ‘front.’ The 
second antenne are very slender; the basal joint does not 
as in the Periceridz constitute a great part of the inferior 
orbital margin, but is very small, seldom reaching the 
‘front, and with the next joint occupies the narrow gap 
intervening between the ‘ front’ and the inner angle of the 
orbit. (In Ceratocarcinus the antennz are completely 
excluded from the orbits.) 
Some fifteen or twenty genera are reckoned in this 
family, of which only one is known in the waters of Great 
Britain. 
Eurynéme, Leach, 1814, has not yet received many 
