540 Orchestia 



Autenna 1, joints of peduucle successively shorter, flagellum shorter tlian 

 peduncle, 4-Jointed. Antenna 2 about Vs as loag as body, ultimate and 

 penultimate joints of peduncle elongate, flagellum 12 — 16-jointed. Gnatho- 

 pod 1 in d, 5*'^ and 6*^ joints strongly produced apically, 6*^ shoi-ter tban 

 5*^, tinger overlapping palm, but not reaching end of apical process. Gnatho- 

 pod 2 in d, 6^^ Joint large, oval, palra not very convex, ending in long 

 groove for apex of the long finger. Gnathopod 1 in Q , o^^ Joint longer 

 than 6*^ not greatly widened distally, 6* narrowly oblong, finger a little 

 longer than palra. Gnathopod 2 in 9, 5*^ Joint not longer than 6*^, hind 

 margin bulging, 6*^ broadly produced beyond the little concave palm and 

 longitudiual finger. Peraeopod 5, 2^ Joint with spines on front and many 

 spinules on hind^ margiu. Uropod 1, rami shorter than peduncle, outer ramus 

 with only apical spines. üropod 3, ramus rather shorter than peduucle. 

 L. 8 mm. 



Flores. 



19. O. grillus (Bosc) 1802 Talitrus g., Bosc, Crust., v.2 p. 152 t. 15 i. 1, 2 j 

 1803 T.g., Latreille,Hist. Crust. Ins., ii.0p.300 | 1840 T.gryllus, Orchestia {pavt.}?, H.Milne 

 Edwards, Hist. nat. Crust.. v.S p. 17 ] 1844 0. g., De Kay, Zool. N.-York, r. 6 p. 36 t. 7 

 f. 19 1 1862 0. g., Bäte, Cat. Amphip. Brit. Mus., p. 18 t". 3 f . 2 | 1847 0. g. {Scamballa 

 sayana Leach in MS.), A. White, Crust. Brit. Mus., p. 86 | 1873 0. palustris, (S. I. Smith 

 in:) A. E. Verrill in: Rep. U. S. Fish Comm., *;. 1 p. 555 | 1893 0. gammarellus (part.)?,. 

 A. DellaValle in: F. Fl. Neapel, «;. 20 p. 511. 



Much resembling 0. gammarellus (p. 532). Pleon segment 3, postero- 

 lateral corners acute, a little produced, margin above almost smooth. Eycs 

 subrotund, rather large, dark, nearer together than their width. Antenna 1 

 about reaching end of penultimate Joint of peduncle of antenna 2. Antenna 2 

 rather slender, flagellum 17 — 25-jointed. Gnathopod 1 in d, 4*^ Joint with 

 concave distal margin, 5*^ Joint with subapical process prominent, narrow, 

 6*^ with apical wideuing strongly produced outward and a little downward, 

 finger matching apical margin. Gnathopod 2 in d, 2*^ Joint not distally 

 widened, 6*^ becoming very large, oval, palm spimüose, subequal to hind 

 margin, oblique, convex between 2 slight depressions, finger large, the point 

 not very acute. Gnathopod 1 in Q , 5*^'^ and 6*^ joints spinöse, 6*^ narrow, 

 parallel-sided, finger matching or overlapping the small, slightly concave 

 palm. Gnathopod 2 in Q , 2*^ Joint broadly laminar, bind margiu nearly 

 straight, front strongly convex except just at distal end, 5**^ rather broad, 

 6*^^ distally produced beyond the slightly oblique finger. Peraeopod 2, inner 

 margin of finger scarcely irregulär. Peraeopods 4 and 5 with 4*^ — 6**1 joints 

 long and slender, even in the largest specimens of both sexes. üropod 1, 

 rami shorter than peduncle, both with marginal spines. Uropod 3, ramus 

 shorter than peduncle. Telson spinulose. L. reaching in o 18, in d 22 mm. 



Atlantic coasts of North America. Under vegetable detritus and sand, also in salt- 

 marshes and up to fresh water; at times above high-water mark in almost dry places. 



20. O. platensis Kreyer 1845 0. p., Kreyer in: Naturh. Tidsskr., ser. 2 v. l 

 p.304 t.2 f.2 j 1862 0. p., Bäte, Cat. Amphip. Brit. Mus., p.l9 t.3 f.3 i 1867 0. crassi- 

 cornis, A. Costa in : Annuario Mus. Napoli, v. 4 p. 38 | 1895 O. c, Chevreux in : Rev. 

 biol. Nord France, v.7 p. 154 1 1873 O. agilis, (S.I.Smith in:) A. E. Verrill in: Rep. 

 U. S. Fish Comm., vA p. 555 t. 4 f. 14 | 1893 0. gammarellus (part.), A. Della Valle in: 

 F. Fl. Neapel, v. 20 p. 499 | 1883 0. tiberiadis, L. Lortet in: Arch. Mus. Lyon, v. 3 p. 190 f. 

 1888 0. incisimana, Chevreux in: C.-R. Ass. Fran(^>., Sess. 17 i\2 p. 346 t. 6 f. 1, 2. 



