446 Elasmopus. Plesioganimanis 



Body srnooth. Pleon segments 1 — 3, postero-lateral corners acute, little produced, 

 Gnathopod 1, 5th Joint little shorter than (yi^. Gnathopod 2, öth Joint broad, QtYi longer 

 than broad, narrower distally, with the distal margin very oblique, not acute, but 

 presenting a broad surface, against which the strong arcuate finger closes, and armed 

 with 4 spines or lobes, of which the inner 2 are small. Peraeopods 3 — 5 rather 

 robust, 2d Joint not serrated. üropod 3, rami subequal, liroader and slightly shorter 

 than the others. 



Port Jackson [East-Australia]. 



E. erythraeus (Kossm.) 1880 Moera erythraea, Kossmann, Reise Roth. Meer., 

 IJ. 2i Malacost. p. 132 t. 14 f . 1 — 8 | 1888 Elasmopus erythraeus, T. Stebbing in: Rep. 

 Voy. Challenger, v.29 p. 516 i 1893 E. rapax (part.), A. üella Valle in: F. Fl. Neapel, 

 V. 20 p. 736. 



Probably the young of another species of Elasmopus. L. about 6 mm. 



Red Sea. 



E. miersi (Wrzeön.) 1879 Maera m., Wrzeäniowski in : Zool. Anz., v.2 p. 348 | 

 1888 M. m., T. Stebbing in: Rep. Voy. Challenger, v.22 p. 502 | 1893 M. m., A. Della 

 Valle in: F. Fl. Neapel, v. 20 p. 732 | 1899 Elasmopus w., T. Stebbing in: Tr. Linu. 

 Soc. London, ser. 2 u. 7 p. 426. 



L. 9 mm. 



Chimbote Bay [Peru]. Under stones in tide-pools. 



E. peruvianus (Dana) 1852 Ämphithoe peruviana, J.D.Dana in: P. Amer. 

 Ac, v.2 p. 215 I 1853 & 55 Gammarus? peruvianus, J.D.Dana in: U. S. expl. Exp., 

 uJ3n p. 958 t. 66 f. 2 | 1893 Elasmopus (part.)?, A. Della Valle in: F. Fl. Neapel, u20 

 p. 454 I 1862 Megamoera peruviensis, Bäte, Cat. Amphip. Brit. Mus,, p. 231 t.40 f. 8. 



Near E. brasiliensis (p. 443), compare also E. delaplata (p. 444). Peraeopods 1 

 and 2 about as long as peraeopod 5, which is longer than peraeopod 4. L. about 12 mm. 



Tropical Pacific (Island of San Lorenzo [Peru]). Among sea-weed on the shore. 



35. Gen. Plesiogammarus Stebb. 



1899 PZesio^ramwarMS (Sp. typ.: P. gerstaeckeri), T. Stebbing in: Tr. Linn. Soc. 

 London, ser. 2 u 7 p. 426. 



Near to Gammarus (j). 460), with 6*^ Joint of gnathopod 1 smaller 

 than that of gnathopod 2, but with marginal inflation of many segments, 

 some dorsal setae but no dorsal spines, peduncle of antenna 1 longer than 

 peduncle of antenna 2, 2*^ Joint of peraeopods 3 — 5 long and naiTow, uropod 1 

 reaching end of the short uropod 3 and telson not cleft to the base. 



1 species. 



1. P. gerstaeckeri (Dyb.) 1874 Gammarus g., B. Dybowsky in: Horae Soc. 

 ent. Ross., u 10 suppl. p. 108 1. 14 f. 5 | 1899 Plesiogammarus g., T. Stebbing in: Tr. 

 Linn. Soc. London, ser. 2 v.7 p. 426 | 1893 Gammarus locusta (part.)?, A. Della Valle 

 in: F. Fl. Neapel, v.20 p. 928. 



Peraeon segments 1 — 7 and pleon segments 1 — 3 with clear marginal 

 swellings, pleon segment 3 on upper sm*face and segments 4 — 6 on bind margin 

 can'ying a few tolerably long setae. Head with short rostral point, at the sides 

 inflated over the eyes. Side-plates 1 —4 small, regularly rounded below. Eyes 

 of varying size and shape, usually renif onn, more rarely roundish or punctif orm, 

 white. Antenna 1 as long as body or sometimes shorter, 4 times as long as 

 antenna 2, peduncle stouter and somewhat longer than peduncle of antenna 2, 

 1^* Joint stout, as long as 2*^ and 3* combined, flagellum 47-jointed, accessory 

 flagellum 3- or 4-jointed. Antenna 2, ultimate Joint of peduncle shorter 

 than penultimate, thickened distally and there carrying a cii'clet of plumose 



