42 
THE VOYAGE OF H.M.S. CHALLENGER. 
Adult ?. 
Length of carapace to base of rostrum, about 
Length of rostrum, about 
Breadth of carapace, nearly’ . 
Length of a chelipede (in the female), about 
Length of first ambulatory leg, about 
Lines. Millims. 
6J 13-5 
3 6-5 
4 10 
7J 16 
12 25-5 
The single specimen I have seen (an adult female) is in somewhat imperfect 
condition, and was dredged at Station 192, near the Ki Islands, lat. 5° 49' 15" S., 
long. 132° 14' 15" E., in 140 fathoms. 
It is at once distinguished from all the recorded species of the genus by the closely 
pubescent and strongly tuberculated carapace, and longer rostral spines. 
Acantlionyx, Latreille. 
Acantlionyx, Latreille, Crust, in Cuvier, Regne Animal, ed. 2, vol. iv. p. 58, 1829. 
„ Milne Edwards (part), Hist. Nat. Crust., vol. i. p. 342, 1834. 
,, Miers, Journ. Linn. Soc. Lond. (Zool.), vol. xiv. p. 650, 1879. 
Carapace suboblong, rounded behind, and with the dorsal surface usually depressed, 
not markedly constricted behind the prominent antero-lateral angles, the lateral branchial 
spines small and not prominent. Prseocular spine prominent, acute. Spines of the 
rostrum united at the base, acute and but little divergent. Post-abdomen in the male, 
in the species I have examined, six-jointed. Eyes small, mobile, but not completely 
retractile. Basal antennal joint narrowing slightly from the base to the distal extremity, 
which is unarmed ; flagellum exposed and visible from above at the side of the rostrum. 
Merus of the exterior maxillipedes truncated at the distal extremity and but slightly 
notched at the antero-internal angle, where it is articulated with the next joint. Chelipedes 
(in the adult male) well developed ; palm compressed, but slightly turgid in the middle, 
and often slightly carinated above ; fingers acute, and having between them, when closed, 
an interspace at the base. Ambulatory legs short, with the penultimate joints more or less 
dilated and compressed and armed with a tooth or lobe on its inferior margin, against 
which the small acute dactylus closes. 
The species of this genus are small and not numerous, and occur both in the Atlantic 
and Indo-Pacific regions in shallow water. The following is a list of them : — 
Acantlionyx lunulatus, Gudrin-Meneville ( = Maia glabra, Latreille; Acantlionyx 
viridis, Costa ; Acantlionyx brevifrons, A. Milne Edwards). Mediterranean 
' and Cape Yerde Islands. 
Acantlionyx petiverii, Milne Edwards ( = Acantlionyx emarginatus, Milne 
Edwards and Lucas ; Acantlionyx debilis, Dana, and Acantlionyx con- 
cameratus, Kinahan, vars. ?). West Indies to Brazil, and California to 
Chili ; Galapagos (A. Milne Edwards). 
