Gammarus punclatus. 177 



2. Gam. punctatus. 



Desc. Body eight lines long, smooth, olive-green, when dead 

 changing to a sand-colour, speckled, particularly on the sides, with 

 minute black dots, and marked on the back with numerous deeply 

 impressed punctures. Antenna: %t^^n^id or annulated with brown; 

 superior nearly as long as the body, the third joint much shorter 

 than the two preceding, the last very long, and armed at each 

 articulation with a whorl of bristles ; inferior thicker and shorter 

 than the superior, with the basilar joint shorter than the second 

 or third. Eyes round, brown, placed between the antennse; after 

 death they become red. Arms with large, nearly equal, ovate- 

 oblong hands, monodactyle, ciliated on their inner margins. A 

 deep semilunar fissure between the wrist and hand, and betweea 

 the wrist and preceding joint of the first pair ; the hand of the 

 second pair with an obsolete tooth, and the fissures less obvious. 

 Clazos conical, sharp, aduucous. Legs monodactyle, nearly of the 

 colour of the body, hairy; the hairs of the two short pairs being 

 generally distributed, those of the three longer pairs collected into 

 little fascicules about the joints. Caudal processes three pairs, bifid, 

 with short branches, — the third pair terminal, conical, and very 

 short. 



Ilab. Amongst confervaa in pools left by the tide, very com- 

 mon near Berwick. 



Obs. In the arrangement of Dr. Leach this is an Ainpithoe. 

 He describes one species, the Cancer Gammarus ruhricaius of 

 Montagu, (Linn. Trans, ix. 99. tab. v. fig. 1.) which differs from 

 ours in the following particulars: — it is of a "reddish, or pale 

 pink" colour; the eyes are crimson, in ours brown, and so dark 

 that if not attentively examined they might be pronounced black ; 

 the hands have no notch or fissure between their articulations ; 

 and, if Montagu's figure be correct, the outline of the body is 

 different. Moreover, in the description, Montagu makes no men- 

 tion of the punctures on the dorsal portion of the segments, a 

 character not likely to have escaped the notice of that excellent 

 naturalist. 



Vol. IIL h 



