Crangonyx 373 



a cilium near the tip (this feature appears to be common in the genus). 

 üropods 1 — 3 extending to about the same point. üropod 1, rami subequal, 

 scarcely half as long as peduncle. üropod 2, rami very unequal, outer 

 half as long as inner, üropod 3 scarcely as long as telson, the ramus 

 veiy small, tipped with 4 or 5 setiform spinules. Telson % as broad as 

 long, tapering slightly to the entii'e, slightly arcuate apex, which is armed 

 with about 10 slender spinules. L. usual 6 — 8, largest d 13-5 mm. 

 Connecticut (wells at Middletown). 



5. C. bifureus 0. P. Hay 1882 C. b., 0. P. Hay in : Amer. Natural., v. lö p. 145 | 

 1894 C. h., Chilton in: Tr. Linn. Soc. London, ser. 2 u6 p. 218. 



Pleon Segments 1 — 3, postero-lateral angles drawn backward iuto a 

 decided tooth. Eyes oval, black. Antenna 1, 1^* and 2*^ joints subequal, 

 3'! % length of 2^, flagellum 24-jointed. Antenna 2 half as long as antenna 1, 

 ultimate and penultiraate joints of peduncle equal, these and the flagellum 

 caiTying sensory organs, which in spirit resemble a lanceolate or oblanceolate leaf 

 having a midrib and parallel veinlets running from this to the margin. 

 Gnathopod 2 with 6*^^ Joint more elongate and with a more oblique palm thau in 

 gnathopod 1. üropod 3, the ramus about % as long as peduncle ; a process of 

 the peduncle is thought perhaps to represent the missing inner ramus. Telson 

 twice as long as broad, sides nearly parallel, cleft nearly -^^ of length, each 

 prong armed at apex with 3 — 5 spines. L. about 9 mm. 



Mississippi (at Macon, from rivulet flowing down the limestone hills into the 

 Noxubee-River). 



6. C. recurvus (Cxrube) 1861 Gammarus r., E. Grube, Ausfl. Triest, p. 137 | 

 1864 & 66 Crangonyx r., E.Grube in: Arch. Naturg., ». 30i p. 200; ü. 32i p.410 1. 10 

 f.l I 1893^0. r., A. Della Valle in: F. Fl. Neapel, t7.20 p. 682 \ 1871 C. recurvatus, S. I. 

 Smith (& A. E. Verrill) iu: Amer. J. Sei., ser. 3 v.2 p.448. 



Back smooth, pleon segments 1 — 3 not longer than the preceding. Side- 

 plates 1 — 4 comparatively deep. Pleon segments 1 — 3, postero-lateral angles 

 (in figure) acute. Eyes small, oval, composed of about 15 Clements, pigment 

 dispersed, black. Antenna 1 a little longer than half the body, flagellum con- 

 siderably longer than peduncle, 14- or lörjointed. Antenna 2 much shorter, 

 ultimate and penultimate joints of peduncle equal, flagellum 5- or 6-jointed. 

 Gnathopods 1 and 2 similar, 5*^ and 6^^ joints about equal in length and 

 breadth, 6*ii longer than broad, subrectangular, palm scarcely oblique in 

 gnathopod 1, a little more so in gnathopod 2, in neither as long as bind 

 margin. Gnathopod 2, 5*^ and ö*'! joints longer than in gnathopod 1. 

 Peraeopods 3 — 5, 2^ Joint oblong oval, with crenulate bind margin. Mar- 

 supial plates, except the last, veiy large, with long setae. üropod 3 very 

 Short, not extending so far as 1^* and 2*^, the ramus shorter than peduncle, 

 with 1 or 2 spines at apex. Telson rather long, cleft to'the middle, apices 

 acute. L. 3 — 6 mm. " 



Island of Cherso. 



C. ermannii (M.-E.) 1840 Gammarus e., H. Milne Edwards. Hist. nat. Crust., 

 V. 3 p. 49 1 1862 Crangonyx e., Bäte, Cat. Amphip. Brit. Mus., p. 179 t. 32 f. 7 | 1893 

 C. e., A. Della Valle in: F. Fl. Neapel, i;.20 p.682. 



Eyes round, small. Antenna 1 the longer, flagellum longer than peduncle. 

 Gnathopods 1 and 2 subequal, alike, 6th Joint ovate, palm oblique, not defined, 

 scarcely leaving any hind margin. Üropod 3 short, scarcely extending beyond 

 preceding, ramus unarmed (Bäte). According to Milne Edwards üropod 3 and telson 

 end in two conical unarmed stylets. L. 15 mm. 



Warm Springs of Kamtchatka. 



