58 
THE VOYAGE OF H.M.S. CHALLENGER. 
The carapace (as in the type) is nearly devoid of hair ; the rostral spines are very 
slightly divergent; there is a well-developed spine at the antero-external angle of the 
basal antennal joint. 
Adult d. 
Length of carapace and rostrum, 
Breadth of carapace, rather over 
Length of a chelipede, nearly 
Length of first ambulatory leg, 
Hyastenus oryx, A. Milne Edwards. 
Hyastenus oryx, A. Milne Edwards, Nouv. Archiv. Mus. Hist. Nat., voL viii. p. 250, pi. xiv. 
fig. 1, 1872. 
„ ,, Miers, Crust. Rep. Zool. Coll. H.M.S. “Alert,” pp. 195, 522, 1884. 
Philippine Islands, 18 fathoms; lat. 11° 37' 0" N., long. 123° 31' 0" E. (Station 208). 
Two adult but small females are referred to this variable species. As is usual in smaller 
examples of this species, the spines of the rostrum are considerably reduced in length ; 
they are much shorter than in A. Milne Edwards’ figure, which is an excellent delineation 
of the adult male. 
The larger female has only the following dimensions : — 
Adult ?. Lines. Millims. 
Length of carapace and rostrum, . . . . . 5J 11 
Breadth of carapace, nearly ...... 3 6 
Lines. Millims. 
6 12 5 
3 7 
5 10 
8-5 18 
Hyastenus elegans, n. sp. (PI. YI. fig. 3). 
The body is covered with a close short pubescence, interspersed amid which are some 
longer hairs. The carapace is shaped nearly as in Hyastenus oryx, to which this species 
is nearly allied, and is armed with tubercles and spines which are much larger and more 
prominent than in Hyastenus oryx. The gastric region is tuberculated nearly as in 
Hyastenus oryx, three of the tubercles being disposed in a longitudinal median series ; 
there is a prominent, conical tubercle on the cardiac region and a yet longer spine on 
the intestinal region ; the hepatic, pterygostomian and branchial regions are tuberculated ; 
there are about five small spines on each branchial region besides some smaller tubercles ; 
the spines of the rostrum are very long (nearly as long as the carapace), slender, and but 
slightly divergent. The orbits, antennae, and outer maxillipedes are nearly as in Hyastenus 
( Chorilia ) oryx ; the tooth at the antero-external angle of the basal antennal joint 
is prominent and spiniform ; the chelipedes and ambulatory legs differ in nothing from 
the same limbs in Hyastenus oryx, except that there exists a small spine at the distal 
