22 IVAR TRÄGÅRDH, (Schwed. Südpolar-Exp. 
species, which I have collected in Egypt and Natal, as well as R. gelida (from 
Greenland) and TroüESSART’s type specimens. 
This has confirmed my opinion as to R. gelida being a distinct species and 
proved that R. gerlachei 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. cylindrica [5, p. 15, 
PI. I, figs 23 — 27] perhaps excepted — do not give enough details with reference 
to the shape of the maxillæ and the ambulacres and these seem to be the very 
organs which, in connection with the shape of the mandibles and the palpi, offer 
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-type, 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 very slightly concave, raised 
abruptly at the extreme back. The condylus of the lower jaw widens at a right 
angle; lower jaw curved upwards very slightly, with raised dorsal edge, provided 
with fine teeth. 
R. gerlachei (Text-fig. 38). The mandibles differ from the gigas-type 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 maxillæ. 
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 ambulacres. 
R. gigas (Text-fig. 43); the pulvillum is more broad and flat, not so strongly 
chitinized as in the other species; the claws are stalked, provided with a sharp 
