268 COLLECTIONS FROM MELANESIA. 



From most of its congeners this species is distinguished by the 

 absence of a distinct rostrum, and the form and armature of the 

 larger chelipede ; the latter character will distinguish it from E. 

 tricarinatus and E. acantholepis, Stimpson, from Japan and Port 

 Jackson, species in which the rostrum is absent. From the fore- 

 going species it is at once distinguished by the longer, slenderer 

 eye-peduncles with shorter basal scales, the form of the chelae, 

 slenderer ambulatory legs, &c. 



11. Petrolisthes japonicus (De Haan), var. inerrnis, Haswell. 



Port Molle (No. 103), several specimens obtained on the beach 

 between tide-marks ; Port Curtis, 7-11 fms. (So. 85), several 

 specimens. 



Other specimens are in the collection of the British Museum from 

 Facing Island, Port Curtis (J. Macgillivray, H.M.S. 'Rattlesnake'); 

 and a small example from Shark Bay, W. Australia (/' T . M. Rayner, 

 H.M.S. ' Herald '), probably belongs here. 



This species is closely allied to the well-known New-Zealand 

 P. elongatus, M.-Edwards, but the chelipedes have a longer, slenderer 

 wrist, and the palm is slenderer and its outer margin is straight, not 

 arcuated. The variety inerrnis is distinguished by Mr. Haswell by 

 having two spines near the distal end of the posterior margin of the 

 wrist, not three as in P. elongatus. De Haan in his description of 

 P. japonicus mentions three, but figures two only. The wrist is even 

 longer and the palm more roughened above than in the Australian 

 specimens ; and the second pair of legs only has the merus-joint 

 bispinulose at apex. 



The Japanese species Petrolisthes pidchripes, designated by White 

 Porcellana pidchripes (List Cr. Brit. Mus. p. 129, 1847), of which the 

 type, from the Madjica-Sima group, is in the collection of the British 

 Museum, is closely allied to the foregoing ; but the chelipedes have 

 a short thick carpus, which is much shorter than the cephalothorax, 

 and has three teeth on its posterior margin ; the distal end of the 

 merus-joints of both second and third ambulatory legs is unarmed. 



12. Petrolisthes lamarckii (Leach ). 



Here are referred several specimens found on the beach at Flinders 

 Island, and one obtained between tide-marks at Port Molle (No. 103). 

 These examples are of small size ; the front is triangulate, somewhat 

 deHexed, sinuated on the margins, concave in the middle line above, 

 narrowed to the apex, which is rounded ; there is a very distinct 

 postocular spine on the lateral margins of the carapace; the chelipedes 

 arc closely granulated above ; the arm has a blunt tooth at the distal 

 end of its inner margin; the inner margin of the wrist has three 

 triangular, not very distant teeth, which decrease in size from the 

 first to the last ; at the distal end of the posterior margin are three 

 small spines. Colour reddish or yellowish ; the first and second 

 ambulatory legs (where the coloration is best preserved) have the 



