22 IVAR TRÂGÂRDH, (Schwed. Südpolar-Exp. 



species, which I liave collected in Egypt and Natal, as well as R. gelida (from 

 Greenland) and Trouessart's type specimens. 



This has confirmed my opinion as to R. gcIida being a distinct species and 

 proved that A', gcrlachei differs in some more respects from R. gigas than appears 

 from T.'s description. 



As a general remark stress must be laid upon the fact that most of the descrip- 

 tions of the species of Rhagidia — Kramer's description of R. cvlindrica [5, p. 15, 

 PI. I, figs 23 — 27] perhaps excepted — do not give enough details with reference 

 to the shape of the maxilla; and the ambulacres and these seem to be the very 

 organs which, in connection with the shape of the mandibles and the palpi, öfter 

 the best means of distinguishing the different species. 



The mandibles. 



R. gigas (from Egypt) (Text-fig. 36); the upper jaw with the dorsal edge flattened 

 near the tip; the anterior hair situated on the exterior side, below this a small, 

 longitudinal ridge; the ventral margin with a sharp, raised edge as long as the 

 distance between the hairs. The lower jaw gradually narrowing and curved upwards 

 throughout its whole length; the tip much higher than the level of the condylus, the 

 dorsal edge not raised. 



R. gigas (Text-fig. 35) (from Natal, van Reenens Kloof, 5,519 f. altitude). 

 Mandibles smaller but of gigas-^y^&, the ventral edge of the upper jaw not so raised 

 and the lower jaw somewhat stouter. 



R. gelida (Text-fig. 39); mandibles very large; the chela comparatively smaller, 

 straighter and stouter. Both hairs situated on small projections, the posterior one 

 on a level with the condylus, the anterior one comparatively larger than in the other 

 species. The upper jaw in front of the anterior hair of even width until near the 

 tip which is curved sharply downward; ventral edge ver\' slightly concave, raised 

 abruptly at the extreme back. The cond\lus of the lower jaw widens at a right 

 angle; lower jaw curved upwards very slightly, with raised dorsal edge, provided 

 with fine teeth. 



R. gcrlachei (Text-fig. 38). The mandibles differ from the gigas-X.y^& partly in 

 the same way as those of R. gelida, the chela being straighter and stouter; dorsal 

 edge of the lower jaw without teeth. 



The niaxillœ. 



Text-figs 41 and 42 show how differently shaped the rostrum of R. gigas and 

 R. gelida are. I have not been able to see the shape of the rostrum distinctly on 

 the mounted specimens of R. gerlachei, sent to me by Trouessart. 



The ambjilacres. 



R. gigas (Text-fig. 43); the pulviUum is more broad and flat, not so strongly 

 chitinized as in the other species; the claws are stalked, provided with a sharp 



