270 COIlECTIOSrS PEbM MELANESIA. 



are slender ; dactyli short, terminating in a small claw. Colour (in 

 the spirit-specimen) pale reddish yeUow, puiictulated with darker 

 red. Length nearly 7 lines (14 miUim.), breadth a little over 6 lines 

 (13 millim.) ; length of chelipe'de about 1^ inch (34 miUim.). 



An adult female is in the collection from Thursday Island, obtained 

 on the beach (No. 167). 



There is also in the Museum collection a female from Port Curtis, 

 Facing Island, two examples from Torres Straits (J. B, Juices), and 

 two from the 'Samarang' collection, of which one is from Koo- 

 Keang-San. 



The three distinct spines on the posterior margin of the arm seem 

 to distinguish this form from the P. hellis of Heller, from the 

 Nicobars — a species, however, which is only briefly characterized. 



It is evidently very nearly allied to Petrolisthes rugosus (M.- 

 Edwards), to which are referred specimens in the British-Museum 

 collection from Karachi {Karachi Museum) and North Australia 

 (Dr. J. R. Elsey), which species, however, has the carapace and 

 ohelipedes covered with weU-defined piliferous crests, tod the teeth 

 of the anterior margins of the wrists much more regular in form 

 and disposition. 



14. Petrolisthes annulipes. (Plate XXIX. fig. B.) 



Petrolisthes annulipes, White, List Crust. Brit. Mm. p. 63 (1847), 

 descript. nulld. ■ 



Carapace moderately convex, scarcely longer than broad, its upper 

 surface and also that of the chelipedes transversely striated ; the 

 striae imbricated and fringed on the anterior margins with close-set 

 short setse ; the front is subtrianf ulate, moderately prominent, 

 slightly concave above, with the apex rounded or subtruncated, and 

 the margins usually minutely spinulose ; there is a spine on the 

 upper margin of the orbit just in front of the eye-peduncles ; the 

 sides of the carapace are armed with about six spines, the first of 

 which (when present) is situated just posterior to the outer orbital 

 angle, the second a little behind it, the third a little within the 

 margin on the front of the branchial region, and the other three on 

 the sides of the branchial region and close to one dtaother. The 

 first exposed joint of the antennae is armed with a spine (see fig. 6). 

 The ischium- and merus-joints of the outer maxHlipedes are trans- 

 versely striated and setose, like the carapace ; the last three joints 

 fringed on their inner margins with very long hairs. The merus- 

 joint of the chelipedes is armed with a denticulated lobe at the 

 distal end of its inner margin ; the carpus or wrist has five denti- 

 culated teeth on its anterior margin, and three or four spines on its 

 posterior margin ; the palm is armed with a series of minute spi- 

 nules on its outer or posterior margin ; the fingers meet along their 

 inner edges, and have their tips incurved and acute. The ambulatory 

 legs are somewhat hairy, the merus-joints in the first three pair's 

 transversely striated and setose, and armed with spinules on their 



