GAMM ARIJS PULEX. 



381) 



Gammarus pulex. 



Gammarus aquaticus. 



Gammarus Fossa/rum. 



Crcrette des rmsseaux. 

 Gamma/rus fiaviatills. 



Desmarest, Cons. Crust, p. 266, tab. 45, fig. 8. 



Zenker, Comment, tie Gamm. pul. tig. A c and 



details. Gervais, Ann. Sci. Nat. 2 ser. iv. 



p. 128. Hosius, Dissert, de Gammari spec. 



p. 19 ; and in Wiegm. Archiv. 1850. i. p. 233. 



Burgersdyk, Annot. de Crust, indig. p. 4. 



Milne Edwards, in Cuvier, Regne An. edit. 



Crochard, pi. 60, fig. 1. Milne Edwards, Hist. 



Nat. Crust, t. iii. p. 48 ? ? Latreille, Hist. 



Nat. Ins. &c. vi. p. 316? Gen. Crust. Ins. i. 



p. 58? Leach, Edin. Ency. vii. p. 402, 432 



(not of Fabricius). Bruzelius, Skand. Ampb. 



Gam. p. 54. Liljeborg, Kongl. Vetensk. Akad. 



Hamll. 1853, p. 449. 

 Leach, Linn. Trans, xi. p. 359. Suppl. Encyc. 



Brit. i. p. 425. Samouelle, Ent. Comp. p. 103. 

 Koch, Deutscbl. Crust. Myr. u. Aracb. h. 5, No. 1 ; 



and Panz. Ins. Germ. Suppl. h. 138, No. 1. 

 Geoffrot, Hist, des Ins. ii. p. 667, pi. xxi. fig. 6 ? 

 Milne Edwards, Ann. Sci. Nat. t. xx. p. 368. 



Zaddach, Prodr. Syn. Crust. Pruss. p. 6 (not of 



Pay nor Rosel). 



The present species bears so near a resemblance to 

 G. locusta, in everything except colour and habitat, that 

 it requires the closest observation to distinguish the two 

 species. In all the marine species the fasciculi of spines 

 upon the dorsal surface of the caudal segments are short 

 and stiff, whilst in this fresh -water species they are 

 mixed with others of a more slender hair-like character. 

 The eyes also are formed of minute black dots, and 

 rounder, though still reniform. The superior antennae 

 have the peduncle extending only to the extremity of 

 the penultimate joint of the peduncle of the lower pair; 

 the secondary appendage is very slender, shorter than in 

 G. locusta, and composed of only three or four articuli. 

 The inferior antennae are rather shorter than the su- 

 perior, they have the olfactory organ largely developed, 

 and the flagellum in the male is very robust. The first 

 two pairs of legs are subequal ; the hands are nearly 

 of the same size, but the second pair have the palm less 



