oAMMAurn.K. 223 



Doubtful S2)ecies. 



38. Gammarus diibius. 

 Gammarus dubiiis, Johusfon, Zool. Journ. iii. p. 178. 



" Antennae subeqiial, rather more than halt' the length of the body ; 

 first joint longer than the second or third. Eyes black, roundish. 

 Gnathopoda snboqual, not much dilated, sparingly ciliated. Pe- 

 reiopoda spiny ; spines not collected into fascicles, but distributed 

 over the entire margins. Pleopoda long, with aciculate branches. 

 Telson consisting of two rather long conical spinous processes, and 

 above them two much smaller papillae. 



'' Length 2 or 3 lines. 



'' Hah. Confervas, in pools near Berwick." — Johnston. 



39. Gammarus maculatus. 



Gammarus niacidatus, Johnston, Zool. Journ. iii. 

 (Not LUjehorg.) 



" Eyes red, large, oblong, running backwards. Gnathopoda alike, 

 with oval and monodactyle gnathopoda, hairy, and partially hairy 

 on the inner margin. 



" Length 6 lines. 



" Hah. Sea-coast near Berwick ; rare ; among corallines dredged 

 from deep water." — Johnston. 



40, Gammarus appendiculatus. 



Gammarus appendicidatus, Say, Journ. Acad. Nat. Sci. Philad. i. p. .177. 

 Edwards, Hist, des Crust, iii. p. 51. 



" Caudal segments and three tenninal segments of the body dentated 

 on their posterior edges. Clypeus not extended beyond the frontal 

 curve. Eyes moderate, oval, hardly extending above the inferior 

 base of the superior antennae. First pair of gnathopoda filiform ; 

 propodos dilated, hav-ing the dactylos on the middle of the tip, short, 

 curved, acute. Second pair m one sex having one of the pair- with 

 the propodos Tcry large, didactyle, nearly equal to one-half of the 

 body, subovate, inferior edge rounded, superior one rectilinear, 

 terminating at the base of the thumb in an obtuse angle ; tip or 

 pabn of the hand tridentate, lower tooth very small ; dactylos 

 reflected nearly rectangidarly ; thumb grooved, groove forming 

 an cmargination at the outer tip for the reception of the tip of 

 the dactylos (in the other sex the second pair of gnathopoda are 

 monodactyle, longer than the first). First three segments of the 

 pleon dentate at the three posterior tips above, with seven strong 



