108 Rathbun — Neiv Crabs from Gulf of Siam. 



Philyra olivacea sp. nov. 



Type. — c?, coast of Lem Ngob, in seine. 



Dimensions. — Length, 9 mm. ; width, 7.8 mm. 



Carapace elongate oval, hepatic facet well defined; elevated portions 

 granulate; from the postero-lateral margin 2 oljlique lines run inward 

 and converge, forming a small triangular area. Front subtruncate, a 

 slight median point; end of maxillipeds visible from above. Eyes long, 

 slender. Strong tooth on lower hepatic margin. Lateral margins of 

 carapace bi-angular. Posterior margin trilobate. Chelipeds granulous, 

 hand % as- wide as long, outer edge straight, inner convex; dactylus }^ 

 longer than outer edge of palm. Third, fourth and fifth segments of 

 abdomen fused, penultimate segment unarmed, wider than terminal half 

 of preceding segment. 



Subfamily ILIIN^. 

 Arcania siamensis sp. nov. 



Type. — 9 , Sound at Koh Chang, 3-5 fatlioms, soft clay. 



Dimensions. — Length with spine, 17.5 mm.; without spine, 15.7 mm.; 

 width with spines, 24.5 mm. ; without spines, 15.5 mm. 



Near J^. septemspinosa (Fabricius); carapace more globular, branchial 

 regions more swollen ; surface densely covered with granules visible to 

 naked eye ; marginal spines shorter, the long lateral spine less than X 

 width of carapace. 



Family HYMENOSOMID.^. 

 Rhynchoplax coralicola sp. nov. 

 Type. — 9, Singapore, on coral reef. 



Dimensions. — Length, 2.2 mm. ; exclusive of rostrum, L8 mm. ; width, 

 1.7 mm. 



Shell thin, spotted with fine black dots, sparingly hairy, ovate, bordered 

 by a raised rim ; only one lateral spine, situated on antero-lateral margin. 

 Rostrum, a long median and two short lateral spines. Chelipeds unarmed, 

 fingers as long as palm. Dactyli of legs spinulous. 



Family 0CYP0DIDJ<:. 



8l'7iFAMrLY MACROPHTHALMIN^. 



Cleistostoma lingulatum sp. nov. 

 Type. — 9 , Lem Ngob, in mangrove swamp. 



Dimensions. — Length, 8.1 nun.; width, 4.5 mm.; width of front, 

 1.3 mm. 



Surface setose, setie retaining iiuid, granules forming clumps and thick- 

 ened lines on elevated parts. Front almost vertical, with 2 transverse, 

 oval, concave surfaces. Upper border of orbit very oblique. Median tooth 

 of epistome long and lingulato. Exognath concealed ; merus of endognath 

 very narrow anteriorly and witli a deep outer sulcus. Legs subcylindrical, 

 with one or two tubercles on their anti'rior margin. 



