194 COLLECTIONS FROM MELANESIA. 



at the distal end of each basal antennal joint two teeth, whereof one 

 is directed downward and one outward. The legs are more or less 

 pubescent. The chelipedes are slender ; the arm or merus-joint 

 denticulated on its lower surface, and armed above with three or 

 four short spines ; the wrist or carpus rather obscurely bicarinatcd ; 

 hand (in both sexes) smooth, slender, naked, somewhat compressed, 

 and twice as long as broad, or even longer ; ringers straight and 

 acute. The ambulator)' legs are of moderate length ; the merus- 

 joints usually bear two well-developed distal spines, but one of these 

 is occasionally absent ; there is usually a short spine or tubcrclo at 

 the distal end of the following joint, which is most distinct in the 

 first pair of ambulatory legs ; daetyli slightly curved. Length of 

 the largest specimen (an adult female) to base of rostrum about 1^ 

 inch (30 mm.), of rostral spines ^ inch (15 mm.), greatest breadth 

 rather over -| inch (22 mm.) ; length of first ambulatory leg about 

 1| inch (38 mm.). 



There are in the first collection several specimens of both sexes 

 from Port Curtis, 7-11 fms. (Nos. 85, 87). In the second collection 

 are two males from Thursday Island, 3-4 fms. (Xo. 175). 



The spines of the dorsal surface of the carapace vary considerably 

 in length. 



Several of the specimens are more or less thickly covered with an 

 overgrowth of Polyzoa and Sertulariaus (Thuiaria and Crisia), and 

 with a species of Zoanihus. 



From P. aculeatus, as described by llilne-Edwards, this variety 

 is distinguished only by the form of the postocular spine (see fig. A), 

 and by the existence (usually) of two spines at the distal end of 

 the merus-joints of the ambulatory legs. From the P. halimoides, 

 recently described by me, it is distinguished by having two spines 

 on each branchial region, the form of the postocular tooth, &c. 

 Several other species of this subgenus have been described, none 

 of which aro to be confounded with P. (Chlorinoides) aculeatus. 

 P. spatulifer, Haswell, a species dredged at Port Stephen, is at 

 once distinguished by its bifurcated rostral spines, &c. 



11. Hyastenus diacanthus (De Haan). 



A male and three females of this very common species are retained 

 for the collection from Thursday Island, Torres Straits, 3-6 fms. 

 (Nos. 130, 175), one was received from Port Denison, another from 

 Port Molle, 14 fms. (93), another from Port Curtis, 0-11 fms. 

 (92), and another from Port Darwin (12 fms.). As is very usual 

 with H. diacanthus, these specimens are more or less covered 

 with sponges, &c. 



I have already referred to the synonyma and general distribu- 

 tion of this species *. 



In a very small female in the collection, from Port Denison, 



* Proc. Zool. Soc. pp. 19, 26 (1879).; Cat. New-Zeal. Crust, p. 9 (1876). 



