CETJSTACEA OF THE MERGUI AECHIPELAGO. 169 



After a careful examination of the typical specimens of these 

 species, I am inclined to regard 8. ungulata, M.-Edw., as identical 

 with 8. affinis, de Haan, and both identical with S. quadrata, 

 Fabr. S. picta, de Haan, is a different form, and also S. erythro- 

 dactyla, Hess. 8. aspera is closely allied to 8. quadrata, Fabr., 

 and is probably a mere local variety of it. 



I am able now to describe two new forms of this section, one of 

 which is closely allied to Heller's 8. aspera, whereas the other is 

 a most interesting form, leading from tbe typical Grapsidce to the 

 8esar'm(S. 



92. Sesarma aspeea, Heller. 



(Compared with the typical specimens of the 'ISTovara' Expe- 

 dition.) 



Sesarma aspera, Heller, Crustaceen der Novara-Heise, p. 63, Taf. vi. 

 fig. 1. 



Three young female specimens were collected in Elphinstone 

 Island. Dr. C. Kcelbel, of Yienna, kindly enabled me to study 

 two typical specimens of B eller's 8. aspera, an adult male from the 

 Ntcobar Islands and a somewhat smaller female Irom Madras. 



Dr. E. Meinert, of Copenhagen, kindly gave me an excellent 

 photograph of Cancer quadratus, Eabricius (Suppl. Entom. 

 Syst. p. 341), together with the exact dimensions of the typical 

 specimen, which is preserved in the Zoological Museum of 

 the University of Copenhagen. I have, moreover, studied the 

 topical specimens of 8. ungulata, M.-Edw^, and of 8. erythro- 

 dactyla, Hess. 



A careful examination has convinced me that 8. ungulata, 

 M.-Edw., and 8. quadrata, Eabr., are identical with 8. affinis, 

 de Haan. 8. quadrata of Milne-Edwards is quite another species. 

 Prof. A. Milne-Edwards sent me a young female specimen of his 

 8. quadrata ; and although I am unable to describe the characters 

 of the adult male, it is evident at first sight that the specimen 

 in question differs from the true 8. quadrata, Eabr., by its cephalo- 

 thorax being almost exactly quadrate, whereas in ;S'. quadrata, 

 Eabr., the cephalothorax is distinctly broader than long. 



8esarma aspera, Heller, is most closely allied to 8esarma 

 quadrata, Eabr. Its distinctive characters are merely the 

 following : — , 



The cephalothorax is not so iarge as that of 8. quadrata, Eabr.; 

 in Heller's type specimens the proportion of the distance 



