540 COLLECTIONS FROM THE WESTERN INDIAN OCEAN. 



GO. Xanthasia murigera, White. 



An adult female and small male from Mozambique, obtained on 

 the beach (No. 237), agree in all particulars with "White's typical 

 specimens in the British-Museum collection from the Philippines 

 ( ( 'uming\ and with a series of specimens from tho ' Herald ' collec- 

 tion, without indication of locality, but labelled as " parasitic on 

 Tridacna." Dana records this curious species from the Fijis (Yanua 

 Levu), and A. Milne-Edwards from Xew Caledonia ; its occurrence 

 at the western limit of the Indo-Pacific Region is now, I believe, 

 recorded for the first time. 



67. Philyra rectangularis. (Plate XLIX. fig. A.) 



Carapace of somewhat rhomboidal form, depressed, about as broad 

 as long, with the angles at the junction of the antero-lateral and 

 postero-lateral margins rounded ; its dorsal surface is everywhere 

 uniformly and very distinctly punctated ; the front projects but 

 little, and its anterior margin is slightly concave. The pterygo- 

 stomian regions are slightly angulated ; the posterior margin of the 

 carapace projects somewhat and is perfectly straight, the postero- 

 lateral angles being right angles. The eyes project slightly from 

 the orbits, whose upper margins are marked with a fissure : the 

 exognath of the outer maxillipedes is nearly as broad as the ischium- 

 joint of the endognath, and reaches nearly to the acute distal end 

 of the merus-joint. The chelipedes (in the female) are of moderate 

 length and slender ; the arm or merus-joint is granulated both 

 above and below, but more thickly on its inferior surface ; its mar- 

 gins are not distinctly angulated ; the palm and wrist are minutely 

 punctated on their upper and lower surfaces, and are granulated on 

 their outer (or posterior) margins ; the fingers are more than half as 

 long as the palms, straight, acute, and are not denticulated on their 

 inner margins ; tho ambulatory legs small and slender, with the 

 dactyli longer than the preceding joints. The colour (in spirit) is 

 light yellowish brown, carapace and chelipedes being punctulated 

 with dusky grey. Length of carapace (of the female) under 3 lines 

 (nearly 6 millim.). 



A single female was collected at the Seychelles, 4-12 fms.(No. 194). 

 The abdomen in this specimen has all the segments, except the first 

 two and the last, coalescent. 



This species is distinguished from nearly all of its congeners with 

 which I am acquainted by the straight posterior margin of the 

 carapace, with its prominent postero-lateral angles. Philyra tu- 

 berculosa, Stimpson *, from Hong-Kong, which it resembles in this 

 character, has the branchial, post-gastric, and genital regions of the 

 carapace tuberculated. Philyra IcevidorsaUs, Miers, from Goree t, 



* Proc. Acad. Nat. Sci. Philad. p. 160 (1800). 



t Ann. & Mag. Nat. Hist. eer. 5, viii. p. 264, pi. xv. fig. 2 (1881). 



