ASELLUS AQUATICUS. 343 
ISOPODA, ASELLIDA. 
NORMALIA. 

ASELLUS AQUATICUS. 
Specific character. Upper antenne reaching to the extremity of the 
peduncle of the lower; flagellum of the lower twice the length of the 
peduncle. Pereion of a greyish colour, mottled with paler markings; pedun- 
cle of the caudal appendages nearly half the length of the slender terminal 
subequal filaments. 
Length of the male, nearly half an inch; female, much smaller. 
Oniscus aquaticus. Linn. Syst. Nat. ii. p. 1061. Roxmmer, Gen. Ins. 
pl. 30, fig. 12. 
Cymothoa aquatica. Fapricius, Ent. Syst. ii. p. 505; Ejusd. Suppl. 
p. 303 (Idotea aq.). 
LD Aselle. Grorrroy, Ins. Paris, ii. p. 672, t. 22, f. 2. 
Asellus aquaticus. OxivieR, Enc. Méth. iv. p. 252. Leacu, Trans. 
Linn. Soc. xi. p. 373. GuERIN M@NEVILLE, 
Icon. R. An. Crust. t. 31, f. 3. SamovE.ie, 
Ent. Compend. p. 110. Wuirr, B. M. Cat. 
Brit. Crust. p. 69; Pop. Hist. Brit. Crust. 
p. 280, pl. 12, f. 6. 
