CRUSTACEA OF THE MEEQUI ATiCHIPELAGO. 75 



The Leyden Museum contains specimens from tlie shores of 

 Amboina and Timor. 



5i. Thalamita sima, M.-Edw. 



Thalamita sima, Milne-Edwards, Hist. Nat. Crust, t. i. p. 460. 



Portunus (Thalamita) arcuatus, de Haan, Fauna Japonica, Crust, p. 43, 

 pi. ii. fig. 2, and pi. xiii. fig. 1. 



Thalamita sima, Alph. Milne-Edwards, I. c. p. 369. 



Two very young individuals were collected at Owen Island. 

 They closely resemble the two species of the genus Thalamonyx 

 described by Prof. A. Milne-Edwards under the names of Thala- 

 monyx Danes and T. gracilipes ; but in Thalamita sima the two 

 median frontal lobes are less prominent, and the carapace is com- 

 paratively more enlarged. I think, however, the genus Thala- 

 monyx may ultimately prove to be identical with Thalamita, so 

 that it would be better to refer the two foregoing species to 

 the latter genus. 



Thalamita sima Las been observed on the coasts of Coromandel, 

 Java, Amboina, New Caledonia, China, and Japan. Its occurrence 

 in the Eed Seals still doubtful, because it is probably represented 

 there by the closely allied Thalamita Poissoni, Aud., which I 

 have proved to be a distinct species (ISTotes from the Leyden 

 Museum, vol. ii. p. 181). 



52. Thalamita petmna, Herhst. (PI. lY. figs. 5 & 6.) 



Cancer prymna, Herhst, op. cit. pi. ivii. fig. 2. 



Thalamita prymna, Milne-Edwards, Hist. Nat. Cms! aces, t. i. p. 461. 



Portunus (Thalamita) prymna, de Haan, Fauna Japonica, Crustacea, 

 p. 43, pi. xii. fig. 2. 



Thalamita prymna, Alph. Milne-Edwards, I. c, p. 360. 



Seven specimens of different size were collected — three at 

 Elphinstone Island, one at Owen Island, and three at King 

 Island. 



The largest specimen is a male, and its carapace is 53 millim. 

 broad; the cephalothorax of an ova-bearing female is only 

 30 millim. broad. 



In all these specimens the fourth antero-lateral tooth of the cara- 

 pace is rudimentary. They present, however, some differences 

 which are probably individual. Thus the upper surface of the 

 cephalothorax and of the legs in the specimens from King Island 

 is densely covered with short hairs, as in Thalamita Danes ; 

 whereas these hairs are nearly wholly absent in the other in- 



