Rathbun — Neiv Crabs from Gulf of Siam. Ill 



Pinnotheres siamensis sp. nov. 



Type. — c?, south of Koli Kiit, 17-20 fathoms, mud. 



Dimensions. — Length, 1.1 mm.; width, 1.05 mm. 



Near P. kutensis. Carapace more strongly angled behind orbit, sur- 

 face deeply punctate ; front plainly bilobed. Propodus of endognath very 

 elongate, dactylns attached on distal half of propodus not far from 

 middle, and reaching end of propodus. Sternum hollowed out in a cir- 

 cular depression in which lies the end of the abdomen. Palms much 

 swollen. Carpal and propodal segments of legs widened in distal half; 

 dactyli subequal. 



SrBFAMll.Y PIXNOTHERELm.lJ. 



Mortensenella gen. nov. 



Dorsal aspect of Pinnixa. Maxillipeds filling buccal cavity, ischium- 

 merus broad, longitudinal, the two segments subequal, subquadrate, 

 fused, but with a faint suture line; palpus small, attached near outer 

 angle of merus, three segments end to end. Exognath exposed and of 

 good size. 



Type and only species, 



Mortensenella forceps sp. nov. 



Type. — c?, Koh Chang, outsiile mangroves. 



Dimensions. — Length, 4.2 mm. ; width, 6.8 mm. ; fronto-orbital width, 

 2.8 mm. ; edge of front, 1.3 mm. ; posterior margin, 4.6 mm. 



Edge of front straight ; lateral angles of carapace rounded ; lateral mar- 

 gins crenulate, with closed fissures. Chelipeds equal ; fingers strongly 

 curved away from each other, making a wide gap ; a truncate tooth at mid- 

 dle of dactylus. Abdomen narrow-triangular, fifth segment constricted at 

 middle; appendages of first segment would exceed abdomen if extended, 

 but they are bent sharply backward opposite posterior margin of first 

 sternal segment, their extremities broadly oval. 



SuBFAMilv ASTIIRNOGNATHIN.E. 



Asthenognathus hexagonum sp. nov. 



Type. — 9 ) north of Koh Kong, 8 fathoms, mud. 



Dimensions. — Length, 5.6 mm. ; width, 7.8 mm. ; fronto-orbital width, 

 4.0 mm. ; width of lower edge of front, 1.7 mm. 



Carapace strongly hexagonal. Front advanced, edge straight, sides 

 oblique. Second leg longest, about twice as long as carapace, and only 

 slightly longer than third leg; first much smaller; fourth most feeble, 

 reaching little beyond merus of preceding pair. 



Family GONOPLACID^. 



Subfamily CARCIXOPLACIN.E. 



Litocheira cristata sp. nov. 



Type. — 9, two miles south of Koh Tutu, 10 fathoms, sandy mud, 

 shells. 



Dimensions. — Length, 5.5 mm. ; width, 7.7 mm. ; fronto-orbital width, 

 5 mm. ; frontal width, 2.8 mm. 



