96 CYAMIDE. 
AMPHIPODA. CYAMIDA, 
ABERRANTIA. 

CYAMUS THOMPSONI. 
Specific character. Head triangular ; antenne very short ; two middle 
segments of body narrower than the preceding and following. First and 
second pairs of legs equal in size, and not larger than the posterior pairs. 
Third and fourth segments with a single very short oval branchia on each 
side. 
Length about one-sixth of an inch. 
Cyamus Thompsoni. Gossr, Mar. Zool. i. p. 131. Ann. Nat. Hist. xvi. 
p. 30, pl. iii. fig. 11 (1855). Wurtr, Pop. Hist. 
Crust. p. 219, fig. 225. 
Cyamus Thomsont. Spence Batre, Cat. Amph. Brit. Mus. p. 368, 
pl. lviii. fig. 5. Ann. Nat. 2nd ser. xx. p. 525 
(Jan. 1858). 
Cyamus Delphinii. Gufirin Méynvittz, Iconogr. R. An. Crust. texte 
p. 25, pl. xxviii. fig. 5 (adult state ?) 
Cyamus gracilis, Spence Barz, Ann. Nat. Hist. 2nd ser. xix. p. 152 
(Feb. 1857). 
Tur animal which forms the type of Mr. Gosse’s 
species is fortunately preserved in the British Museum 
collection, and has served us for the accompanying figure. 
It is evidently in an immature state, as shown by the 
small size of the antennz, the uniform size of the legs, 
and the rudimental condition of the branchiz ; the legs, 
however, are considerably stronger than in the young 
