Elasmopus 441 



34. Gen. Elasmopus A. Costa 



1853 Elasmopus (Sp. uu.: E. rapax), A. Costa iu: Rend. Soc. Borbon., n. ser. v.2 

 p. 170, 175 I 1871 i;., A. Boeck in: Forh. Selsk. Christian., 1870 p. 212 | 1888 E., T. 

 Stebbing in: Rep. Voy. Challenger, r. 29 p. 1018 | 1893 E., A. Della Yalle in: F. Fl. 

 Neapel, u 20 p. 732 | 1894 E., G. 0. Sars, Crust. Norway, v. 1 p. 520 | 1862 Megamoera 

 (part.), Bäte (& Westwood), Brit. sess. Crust., v. 1 p. 400. 



Head with lateral lobes rounded, Side-plates 1 — 4 usually well deve- 

 loped and the 4*^ excavate behind and deeper than 5*^. Antenna 1 longer 

 than antenna 2, 2*^ Joint subequal to 1^*, accessoiy flagellum seldom long. 

 Antenna 2, flagellum short. Mouth-parts in general as in Maera (p.433), but 3*^ 

 Joint of mandibular palp usually falcate, and pectinate with spinules. Maxilla 1^ 

 outer plate sometimes with only 7 spines. Guathopods 1 and 2 as in Maera. 

 Peraeopods 3 — 5 robust, üropod 3 reaching little or not at all beyond. 

 the others, rami broad, not long. Telson rather small. deeply cleft. 



9 accepted and 4 doubtful species. 



M 



Synopsis of accepted species: 



One or more of the segments dorsally dentate — 2. 

 None of the segments dorsally dentato — 4. 



j Only one segment dorsally dentate 1. E. subcarinatus . p. 441 



) Four segments dorsally dentate — 3. 



/ Gnathopod 2, palm very oblique 2. E. diemenensis . p. 442^ 



) Crnathopod 2, palm nearly transverse 3. E. suensis . . . . p. 442 



j Gnathopod 2, 6th Joint fringed with very long setae 4. E. brasiliensis . . p. 443 



4 I Gnathopod 2, 6th Joint not fringed with very long 

 l setae — 5. 



[ Gnathopod 2, 6*^ Joint with cup-like hollow to 



5 ; i-eceive finger-point 5. E. pocillimanus . p. 44& 



( Gnathopod 2, 6th Joint without cup-like hollow — 6. 



j Uropod 3, rami obtusely lanceolate G. E. delaplata . . . p. 444 



J Antenna 1, accessory flagellum very short ... 7. E. rapax p. 444 



Cropod 3, rami truncate — 7. 

 Antenna 1, accessory flagellum 

 Antenna 1, accessory flagellum well developed — 8. 



9. E. boeckii . . . . p. 445 



J Gnathopod 2, palm transverse 8. E. viridis . . . . p. 445 



I Gnathopod 2, palm oblique 



1. E. subcarinatus (Hasw.) 1879 Megamoera sub-carinata, Haswell in: P. Linn. 

 Soc. N. S. Wales, vA p. 335 t. 21 f. 4 | 1884 Moern s., Chilton in: N. Zealand J. Sei., 

 v.2 p. 230 I 1888 Elasmopus s., E. peisetosus, T. Stebbing in: Rep. Voy. Challenger, 

 17.29 p. 1019 t. 98 I 1893 E. suhcarinatus, A. Della Valle in: F. Fl. Neapel, u20 p. 733 | 

 1882 Moera petriei, G.M.Thomson in: Tr. N. Zealand Inst.,- r. 14 p.236 t.l8 f. 3 | 1883 

 M. p., Chilton iu: Tr. N. Zealand Inst., v. 15 p. 82 t. 2 f. 4a. 



Pleon segment 4 behind the dorsal depression bicarinate, the 2 apical 

 teeth slightly inclined one toward the other. Head, lateral lobes broadly 

 rounded, a small accessory lobe below the principal. Side-plate 1 somewhat 

 produced forward, 4**> the largest, much deeper than 5**». Pleon segment 3, 

 postero-lateral corners acute, a little produced. Eyes large, reniform or 

 oval, dark, advancing on to lateral lobes of head. Antenna 1 elongate, 

 1^* Joint about as long as 2^, rauch stouter, S^ not long nor yet very 

 Short, flagellum longer than peduncle, 50 — 60-jointed, accessory flagellum 

 6-jointed. Antenna 2 mucli shorter, ultimate Joint of peduncle shorter than 

 penultimate, flagellum shorter than peduncle, 14 — 17-jointed. Upper lip 



