Crustacea Decapoda and Stomatopoda. 227 



Rhynchoplax exiguus, Kemp. 



1917. Rhynchoplax exiguus, Kemp, Rec. Ind. Mus., XIII, p 260, fig. 10. 



A very small species without any strongly marked characteristics. Ten specimens 

 were found by Dr. Annandale in the outer part of the Tale Sap, on the mainland 

 opposite the western end of Koh Yaw. They were living in lumps of turf that had 

 fallen inlo the lake owing to the undermining of the banks. The specific gravity of 

 the water was about i' 00625. 



Family OCYPODIDAB. 



Subfamily OCYPODINAE. 



Genus Gelasimus^ lyatreille. 



Gelasimus annulipes, lyatreille (Milne- Edwards). 



igoo. Gelasimus annulipes, Alcock, Journ. Asiat. Soc. Bengal, 1,XIX, p. 353. 

 1915. Gelasimus annulipes, Kemp, Mem. Ind. Mns., V, p. 22X. 



A colony of this abundant species was found by Dr. Annandale at Kaw Deng at 

 the mouth of the Tale Sap. The claws of large males were of a pale dull yellow colour 

 in life. No specimens were observed more than a few hundred yards within the mouth 

 of the lake, the water being practically as salt as that of the Gulf of Siam. 



Subfamily SCOPIMERINAE. 



Genus Dotilla, Stimpson. 



Dotilla wichmanni, de Man. 



1892. Dotilla wichmanni, de Man, in Weber's Zool. Ergebn. Reise Niederland. Ost -Ind., II, 



p. 308, pi. xviii, fig. 8. 

 1895. Dotilla wichmanni, de Man, Zool. Jahrb., Syst., VIII, p. 577- 



1910. Dotilla wichmanni, Rathbun, Dansk. Vid. Selsk. Skrijt. (7), Naturvid. og Math., V, p. 324. 

 . 1918. Dotilla wichmanni, Tesch, Decap. Brachyur. ' Siboga'-Exped., I, p. 45. 



A large number of specimens were obtained at Kaw Deng at the mouth of the 

 Tale Sap on the opposite side of the channel from Singgora. 



The series includes some very fine individuals with carapace nearly 8 mm. in 

 length and consequently much larger than any of de Man's original specimens, none 

 of which exceeded 5 mm. In males between 6 and 8 mm. in length the carapace bears 

 three large angular projections on either side ; two of these are situated, one behind 

 the other, on the outer side of the deep groove that borders the lateral margin, while 

 the third, which is more spinose in character and possesses a corneous apex is situated 

 on the side-wall, immediately beneath the small tooth that defines the upper and outer 

 limit of the orbit (text-fig. i). These projections are not seen in females or small 

 males. 



In large males, also, there is a short but high ridge on the inner face of the carpus, 

 situated close to the meral articulation and easily visible in dorsal view. There is no 



