GAMMARID.K. 1(J.J 



few cilia ; dactylos senated upon the iutcnial margin. Second 

 pair of guathopoda, a\ ith the exception of being smaller, resembling 

 the first pair in form. The rest of the animal bears a close affinity 

 to .V. Gn/llotal^Hi, except in colour, which in tliis species is cor- 

 neous, very transparent, hanng a few pink markings, and generally 

 sparsely covered, except along the dorsal suiface, with black spots. 

 Length — ^ths of an inch. 



Hah. Ox\vich Bay, S. Wales (C. S. B.) ; Coast of Norway {Rathlce 

 and LUjthQry) ; amongst Nullipore, Cumbrae, N. B. (Robertson). 



This species may be the female of one of the preceding ; but it 

 differs considerably in the form of the posterior margin of the an- 

 terior segments of the pleon, as well as in colour. It was the only 

 species I took on the coast of Wales, and must occupy for the present, 

 I think, a position distinct from the others. 



4. Microdentopus tenuis. (PI. XXX. fig. 4.) 

 Gammarus tenuis, Daua, U. S. Explor. Exped. p. 950. pl. Go. f. 5. 



" Slender ; coxae narrow. Front margin of either side of head a little 

 prominent. Eyes round, small. Superior antenna? somewhat shorter 

 than the body, very slender, terete ; first joint of peduncle longer 

 than the third, second twice as long; flagellum slightly longer 

 than the ba;se, foiu'teen-articulated, setae longer than the articuli ; 

 secondaiy appendage very short. Inferior antennae much shorter 

 than the superior, setae longer, base much longer than base of 

 superior ; last two joints long and subequal, the preceding very 

 short ; flagellum five-aiiioulated, not longer than last basal joint. 

 First pair of gnathopoda of medium size ; propodos oblong, some- 

 what larger towards apex and oblicjuely truncate, margins setose in 

 tufts, an angle at the lower Umit of truncation, palm not excavate ; 

 dactylos about half as long as propodos. Second pair much smaller 

 than first. Last three pairs of pcreiopoda very unequal in length ; 

 seventh very much longer than sixth pair. 



" Length 3 lines. 



" Hah. Sooloo Sea, in G^ fathoms water, coUeeted Februaiy 2nd, 

 1842."— Z)rt»a. 



This species closely resembles M. anomalus of the British coast. 



5. Microdentopus versiciilatus. (Plate XXX. fig. 5.) 



Lembos vorsiculcitus, Speiice Hate, Brit. Assoc. Report, 1855 ; Aiiit. 

 Nat. Hist. P^eb. 1857. 



White, Hist. Brit. Crust, p. 180. 



Eyes small, round. Secondaiy appendage to the superior pah- of 



antenna: uniai-ticulate. First pair of gnathopoda having the 



