LIGIA OCBANICA. 445 
pl. xiii. f. 1. Kainanan, Nat. Hist. Rev. iv. 
279, pl. xx. f. 7-10. Gossz, Man. Mar. 
Zool, i. fig. 241. 
Oniscus aquaticus. Bastzr, Opuse. Subs. ii. t. 18, f. 4. 
(Var.) Ligia scopulorum. Leacu, Edinb. Ene. vii. p. 406. Linn. Trans. 
xi. p. 374. 
Tuis is the largest British species in the family, from 
the rest of which it also differs by being found under 
stones, &c., in damp places on the shores of the ocean. It 
has the upper surface of the body slightly rugose, being 
covered with depressed granulations. The first segment 
of the body has a deep transverse impression immediately 
behind the head. The segments of the body have the 
lateral margins thickened, curved, and terminating behind 
in a rather sharp angle. The outer antenne are about 
two-thirds of the length of the entire animal; they are 
robust, with the fourth and fifth joints much larger than 
all the rest. The flagellum differs in the number of 
articuli, probably on account of the difference in the 
ages of the different individuals. The upper lip is entire, 
and rounded at its free anterior margin. The lower lip, 
on the contrary, is very deeply incised in the middle, 
with the interior angles of the incision setose. The 
mandibles are strong, armed with two compound teeth, 
and with a strong incurved molar plate. In fig. d’ the 
mandible is seen laterally, the inner tooth and plate not 
being visible from being on the same plane as the upper 
tooth. The inner maxille are formed of two terminal 
lobes, of which the outer is terminated by several strong 
straight bristles, whilst the inner is shorter, and armed 
with three deflexed setose bristles. The outer maxille 
have the two terminal divisions formed into two short 
joints, with two or three strong short bristles on the out- 
side of the penultimate joint. The preceding portion 
has its inner apical angle produced into a setose fleshy 
lobe. 
