CRUSTACEA. 195 



4 fms. (No. 122), length to base of rostrum little over 5 lines 

 (11 mm.), and in a small, male from Dundas Straits i Xo. 101), the 

 rostral spines are relatively somewhat shorter, and there are only- 

 very small tubercles in the place of the lateral epibranchial spines: 

 it is not improbably a young example of IF. djacanthus. There 

 are specimens presenting very similar characters in the collection 

 of the British Museum without definite locality (//.J/X i Samarang ') 

 and from Pcnang (India Museum ). 



There are specimens in the British-Museum collection from the 

 following points on the Australian coast: — Dunk Island, and lat. 

 20° 58' S., long. 14'.)° 12' E., between Cumberland Island and 

 Slade Point (J. MacgiUivray, H.M.S. ' Rattlesnake '), Brisbane Water 

 (purchased), Moreton Bay (purchased), .Swan Eiver (Bring), 

 Shark Bay, "West Australia (Rayner, H.M.S. ' Herald '). 



12. Hyastenus (Chorilia) oryx. 



Hyastenus oryx, A. M.-Edward8, Nouv. Arehiv. Mas. Hist. Nat. viii. 

 'p. 250, pi." xiv. fig. 1 (1872) ; HasweU, Proa Linn. Soc. N. S. 

 Wale.*, iv. p. 442 (1880) ; Cat. Austr. Crust, p. 20 (1882). 



To this species are referred specimens from several different 

 localities ; e. g. from the first collection two males and a female 

 from Port Molle — the males obtained between 5 and 14 fms. (Nos. 

 93, 118), and the female on the beach (No. 95) ; and a female 

 from Port Denison, 4 fms. (No. 122) ; also from the second collec- 

 tion a good series from Thursday Island, 3-5 fms. (Nos. 105, 177), 

 and Prince of Wales Channel, 7 fms. (No. 109), one female. 



M. A. Milne-Edwards's types were from New Caledonia ; Mr. 

 Haswell records this species from Darnley Island, Torres Straits ; 

 and there are specimens in the collection of the British Museum 

 from Raine's Islet, North-east Australia (J. B. Jukes), Shark Bav, 

 "West Australia (Rayner, H.M.S. 'Herald'), and other Austra- 

 lian specimens without special indication of locality (Boiverbank) ; 

 also from the Philippine Islands, Corregidor (Cuming), and Chinese 

 seas (H.M.S. ' Samarang } ). 



In the second part of this Report its occurrence is noted at Provi- 

 dence Island, Mascarenes. 



The length of the rostral spines and prominence of the prseocular 

 tooth or lobe seems to vary considerably in this species with the age 

 of the specimen. I regard the Lepidonaxia dejtlippii of Targioni- 

 Tozetti *, founded on a female example, as very possibly a mere 

 variety of H. oryx, from which it scarcely differs except in these 

 particulars and in the less numerous and prominent tubercles of the 

 carapace. Certainly it is congeneric with that species. 



* ' Zoologia della Magenta :' Crostacei, p. 5, pi. i. figs. 4-6, 8, 10, 11 (1877). 



o2 



