Gammarus spinipes. 417 



specimen of the animal before me, which may be the Dor. Argo of Bri- 

 tish authors (though our descriptions differ very considerably), but that 

 this is quite distinct from the Dor. Argus of Lamarck, and probably also 

 from Cuvier's Dor. tuberculata. The want of an opportunity to consult 

 the figures and references of authors, compels me to leave the subject in 

 this uncertainty. 



Of the genus Gammarus, as defined by Lamarck, I have had occasion 

 to describe five species, new to our coasts ; and of late another has oc- 

 curred to me, different from any I had previously seen, and apparently 

 also a non-descript. 



Gammarus spinipes. 



Gamm. corpore albo, laevi, lineis rubris transversis picto ; palma pedis 

 secundi dilatata, apice triangulari, monodactyla, spina vahda in- 

 ferne terminate. 



Hab. Littora maris Britannici. 



Desc. Body i of an inch long, smooth, white, with transverse red 

 lines, which run between the segments. Antennce 4-jointed : superior 

 longest, the basal joint very short, second and third equal, the terminal 

 one longer than both ; no seta : inferior with all the joints nearly of 

 equal lengths. Eyes scarlet, round. First pair of hands short, small, 

 scarcely dilated, monodactyle. Second pair with the palm much di- 

 lated, armed with a single claw, and beneath with a conical spine, much 

 like a claw. Between these there is a triangular process. Legs of four 

 elongated joints, the femoral rather dilated, and the tarsal terminated by 

 a single, rather long, curved claw. The first (not counting the two pair 

 of anterior ones, considered as arms) are slender, and slightly spinous, 

 but as we proceed backwards, they become stronger, more spinous, and 

 have the second or tibial joint remarkably dilated and pointed. Tail ter- 

 minated by tlaree pairs of stalked and forked processes, the stalk longer 

 than the straight conical smooth branches. 



Obs. I found this species among Sertularice taken from a fishing 

 boat, so that it probably inhabits deep water. I cannot refer it to any 

 described species. It surely cannot be the Jassa pulchella of Dr. Leach. 

 The brevity of the descriptions of that eminent naturalist often leaves a 



Vol. IV. F F 



