802 
GAMMARIDiB, 
AMPHIPODA . 
NAT ATOM A. 
OA MM A RIDES. 
Genus— B ATHYPOREI A. 
Bathyporeia. Lindsteom. Bidrag Ostersjons, Invert. Faun, in Ofvers. 
Kongl. Yet. Akad. Forhandl. 1855, p. 59. Nat. Hist. 
Review, Jan. 1857, p. 43. White, Hist. Brit. Crust, 
p. 187. 
Thersites. Spence Bate, Rep. Brit. Assoc. 1855. p. 59. Ann. Nat. 
Hist. 2 ser. xix. p. 146. 
Generic character. Superior antennae short ; having the first 
joint of the peduncle large and tumid ; the second articulating 
on the infero-distal extremity of the first, and furnished with a 
secondary appendage. Inferior antennae slender ; twice as 
long as the superior ; mandibles with a tri-articulate appendage. 
First pair of gnathopoda subchelate ; second having the dactylos 
wanting. Posterior pair of pleopoda biramous, the longer 
branch being bi-articulate. Telson double. 
The superior antennae in this genus are much shorter 
than the inferior, having the basal joint greatly swollen, 
and its extremity oblique ; hence the peculiar position 
which the second joint of the peduncle holds to the first, 
the articulation, instead of being at the extremity of the 
joint, being at the distal end of the inferior margin ; 
thus the second articulates with the first joint almost 
at a right angle: the other two joints are generally 
short, and the flagellum is never long, and is furnished 
at its base with a secondary appendage. The inferior 
antennae are much longer than the superior, and 
more slender. The mandibles are furnished with an 
appendage. The first pair of legs are subchelate. The 
