Orchestia 541 



Pleon Segment 3, postero-lateral corners quadrate, margin above serrulate. 

 Eyes elliptie, black, nearer together thau the louger diameter. Antenna 1 scarce- 

 ly reaching end of penultimate Joint of peduncle of antenna 2. Antenna 2 less 

 tiian half as long as body, peduncle stout, ultimate Joint longer than penultimate, 

 flagellum shorter than peduncle, taperiug rather conspicuously, 12 — 15-jointed, 

 strikingly flatteued. Guathopod 1 in d, 5*1^ and 6*'^ joints both strongly 

 produced distally on hind margin, the 6*'' rather the more stoutly and a 

 little downward, finger matching apical margin. Gnathopod 2 in d, 2*i Joint 

 not widened distally, 6*^ rather large, broad, palm more or less oblique, 

 smoothly convex or having near the finger-hinge a broad spinulose convexity, 

 followed by a much smaller lobe between 2 little notches, the long curved 

 finger closing down with a narrow apical piece into the pocket adjoining 

 tlie 2^ notch. Gnathopod 1 in Q , 5**^ Joint a little subapically widened, 

 6^^ slightly narrowed distally, with a feebly developed palm, which is 

 overlapped by the finger. Gnathopod 2 in 9 , 2*^ Joint laminar, the expansion 

 narrowing distally, 5*^ with free part of hind margin evenly convex, 6^^^ not 

 much shorter than 5*'', the minute finger slightly oblique. Peraeopod 2, 

 finger abruptly narrowed at the nail. Peraeopods 3 — 5, 4**^ Joint thick, 

 5*^ Joint in peraeopods 4 and 5 also thick, but without any great widening. 

 Branchial vesicles of gnathopod 2 extremely sinuous. Üropod 1, apical spines 

 on both rami, marginal only on one. üropod 2 stout. üropod 3, ramus 

 rather shorter than peduncle. Telson spinulose. Colour duU greyish brown 

 (Kr0yer). L. 10—15 mm. 



Banks of Rio de la Plata (N.W. of Montevideo); Atlantic coasts of North- America 

 (tVomBay ofFundj* to New Jersey); Bermudas; Mediterranean ; Lake of Tiberias [Palestine]. 



21. O. sulensoni Stebb. 1899 0. s., T. Stebbing in: Tr. Linn. Soc. London, 

 ser. 2 ^;. 7 p. 400 t. 30 C. 



9 unknown. — ö. Integument (in spü'it) membranaceous, iridescent. 

 Side-plates not deep. Pleon segment 3, postero-lateral corners quadrate, 

 point scarcely produced. Eyes not very large. Antenna 1, 1*** Joint at least 

 as broad as long, 2*^ and 3*i each slightly longer, fiagellum with 4 joints, 

 together about as long as 3*^ Joint of peduncle. Antenna 2, peduncle stout, 

 ultimate Joint rather longer than penultimate, flagellum shorter than peduncle, 

 18 — 21-jointed. Gnathopod 1, 4*^^» Joint without apical process, 5**^ with 

 prominent, narrowly rounded, distal pellucid process, 6*^^ oblong, wideuing 

 very slightly to the palm, which has no conspicuous process and is over- 

 lapped by the finger. Gnathopod 2, 2*^ Joint comparatively slender, 5*^ very 

 small, completely masked by 4*'', 6*^ very large, fringed with spinules on 

 the hind margin, widening to the palm, which is moderately oblique, spinulose, 

 smoothly convex between a blunt defining tooth and a deep depressiou near 

 the finger-hinge, the depression corresponding with a rounded process of the 

 finger's inner margin. Peraeopod 1 conspicuously longer than peraeopod 2, 

 both slender. Peraeopod 2, finger short, with 2 notches. Peraeopods 3 

 and 4, 2* Joint oval. Peraeopod 5 having its 2^ Joint considerably larger, 

 and the oval modified by the straightness of its hind margin, the remaining 

 joints slender. üropod 1, upper ramus with lateral spines, rather shorter 

 than lower ramus, which has no lateral spines. üropod 2, rami equal, both 

 with lateral spines. üropod 3, ramus not half as long as peduncle. L. 10 mm. 



Madeira? 



22. O. parvispinosa M.Weber 1892 0. p., M. Weber, Reise Niederl. O.-Ind., 

 V. 2 p. 566 f. 17—19. 



