REPORT ON THE BRACHYURA. 
57 
As regards the distribution of the species, Hyastenus oryx, Hyastenus spinosus, and 
Hyastenus ovatus are, I believe, the only species which have as yet been recorded from the 
western division of the Oriental region, and Hyastenus longipes from its eastern limits 
(coast of Oregon). 
Hyastenus elegans, Miers, and Hyastenus japonicus, Miers, are the only deep-water 
species as yet described ; the former occurred, as mentioned below, near the Ki Islands 
in 140 fathoms (Station 192), the latter in the Japanese Seas, in 100 fathoms; the other 
species occur in the Chinese, Japanese, Indian, Malaysian, Australian, and Polynesian 
Seas, at depths not exceeding 50 fathoms. 
/ 
Hyastenus cliacantlius (de Haan). 
Naxia diacantha, de Haan, Crust, in Siebold, Fauna Japonica, p. 96, pi. xsi. fig. 1, and pi. G, 
1839. 
Hyastenus diacanthus, A Milne Edwards, Nouv. Arcliiv. Mus. Hist. Nat., vol. viii. p. 250, 1872. 
Arafura Sea, in 49 fathoms, lat. 8° 56' 0" S., long. 136° 5' 0" E. (Station 190), a female 
in soft and very imperfect condition ; a small and young female dredged at the Philippines 
in 18 fathoms, lat. 11° 3 7' 0" N., long. 123° 31' 0" E. (Station 208), with Hyastenus 
oryx, also probably belongs to this species ; it has short and but slightly divergent 
rostral spines and the lateral branchial teeth are obsolete. 
Young specimens of this species bear a very close resemblance to Hyastenus planasius, 
but may apparently be distinguished by the more hairy carapace, the generally longer 
and more divergent rostral spines, and the absence of the well-developed spine at the 
antero-external angle of the basal antennal joint, which exists in Hyastenus planasius. 
The dimensions of the small female are — 
Adult ?. 
Lines. 
Millims. 
Length of carapace and rostrum, rather over . 
5 
11 
Breadth of carapace, ..... 
21 
5-5 
Length of a chelipede, .... 
7-5 
Length of first ambulatory leg, 
6 
12-5 
The rostral spines in this example are nearly as in Hyastenus planasius. 
Hyastenus planasius (Adams and White). 
Pisa planasia, Adams and White, Crust. Zool. II.M.S. “Samarang,” p. 9, pi. xi. figs. 4, 5, 1848. 
Hyastenus planasius, A. Milne Edwards, Nouv. Arcliiv. Mus. Hist. Nat., vol. viii. p. 250, 1872. 
An adult male was dredged south of New Guinea in 28 fathoms, lat. 9° 59' 0" S., 
long. 139° 42' 0" E. (Station 188). 
(zool. CHALL. EXP. — PART XLIX. — 1886.) 
Ccc 8 
