76 
THE VOYAGE OF H.M.S. CHALLENGER. 
Pericera, Latreille. 
Pericera, Latreille, in Cuvier, Regne Animal, ed. 2, vol. iv. p. 58, 1829. 
„ Milne Edwards (pt. ), Hist. Nat. Crust., vol. i. p. 334, 1834. 
,, A. Milne Edwards (pt.), Crust, in Miss. Sci. au Mdxique, vol. v. p. 49, 1873. 
„ Miers, Journ. Linn. Soc. Lond. (Zool.), vol. xiv. p. 664, 1879. 
The carapace is subpyriform, rather convex, with the dorsal surface uneven, tuber- 
culated or spinose ; the lateral margins armed with a series of long spines ; the prseocular 
spine is well developed. The rostrum is composed of two well-developed spines, which 
are not deflexed, and are divergent from the base ; the orbits are small and tubular, but 
do not project as in Macrocceloma. The post- abdomen (in the male) is distinctly seven- 
jointed. The eyes are small, retractile within the orbits. The basal antennal joint is 
very considerably enlarged, and is armed with one or two small distal spines or tubercles, 
which are not visible in a dorsal view ; the flagellum is sometimes concealed by the 
rostral spines, sometimes laterally exposed at the sides of the rostrum. The merus of 
the exterior maxillipedes is distally truncated, with the antero-internal angle emarginate 
and the antero-external angle rounded or subacute. The chelipedes (in the adult male) 
are well developed ; palm elongated and sub cylindrical or somewhat compressed, but not 
dilated or enlarged ; fingers without any or with but a small intermarginal hiatus at base 
when closed ; ambulatory legs moderately elongated, with the joints subcylindrical, 
without spines ; dactyli nearly straight. 
The following species are referable to the genus as thus restricted : — 
1. Carapace without spines on the dorsal surface : — 
Pericera cornuta (Herbst) ( = Chorinus armatus, Randall). East Coast of 
United States; West Indies; Brazil; Cape Colony. 
Pericera ccelata, A. Milne Edwards. Idolos Islands ; Havana, to 175 fathoms 
(perhaps a variety of Pericera cornuta). 
2. Carapace with dorsal spines : — 
Pericera spinosissima, Saussure. West Indies. 
Pericera ovata, Bell. Galapagos Islands, 
Pericera cornuta, Milne Edwards. 
Pericera cornuta, Milne Edwards, Hist. Nat. Crust., vol. i. p. 335, 1834; Atlas du R&gne 
Animal de Cuvier, Crust., ed. 3, pi. xxx. fig. 1. 
„ „ A. Milne Edwards, Crust, in Miss. Sci. au Mexique, pt. 5, vol. i. p. 51, 1873. 
Chorinus armatus, Randall, Journ. Acad. Nat. Sci. Philad., vol. viii. p. 108, 1839. 
An adult male is in the collection, labelled as from “Simon’s Bay, 10-20 faths.” 
This example is of rather small size, as the following measurements show ; it differs in 
