CRUSTACEA OF THE MERGUI ARCHIPELAGO. 169 
After a careful examination of the typical specimens of these 
species, | am inclined to regard S. ungulata, M.-Edw., as identical 
with S. afinis, de Haan, and both identical with S. quadrata, 
Fabr. S. picta,de Haan, is a different form, and also VN. erythro- 
dactyla, Hess. 8S. aspera is closely allied to S. guadrata, Fabr., 
and is probably a mere local variety of it. 
IT am able now to describe two new forms of this section, one of 
which is closely allied to Heller’s S. aspera, whereas the other is 
a most interesting form, leading from the typical Grapside to the 
Sesarme. 
92. SESARMA ASPERA, Heller. 
(Compared with the typical specimens of the ‘ Novara’ Expe- 
dition.) 
Sesarma aspera, Heller, Crustaceen der Novara-feise, p. 63, Taf. vi. 
figs). 
Three young female specimens were collected in Elphinstone 
Island. Dr. C. Keelbel, of Vienna, kindly enabled me to study 
two typical specimens of H eller’s S. aspera, an adult male from the 
Nicobar Islands and a somewhat smaller female from Madras. 
Dr. F. Meinert, of Copenhagen, kindly gave me an excellent 
photograph of Cancer quadratus, Fabricius (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 
typical specimens of S. ungulata, M.-Edw., and of SN. erythro- 
dactyla, Hess. 
A careful examination has convinced me that S. wngulata, 
M.-Edw., and S. guadrata, Fabr., are identical with S. affinis, 
de Haan. 8S. guadrata of Milne-Edwards is quite another species. 
Prof. A. Milne-Edwards sent me a young female specimen of his 
S. guadrata; and although lam unable to describe the characters 
of the adult male, it is evident at first sight that the specimen 
in question differs from the true S. guadrata, Fabr., by its cephalo- 
thorax being almost exactly quadrate, whereas in S. guadrata, 
Fabr., the cephalothorax is distinctly broader than long. 
Sesarma aspera, Heller, is most closely allied to Sesarma 
quadrata, Fabr. Its distinctive characters are merely the 
following :— . 
The cephalothorax is not so large as that of 8. guadrata, Fabr.; 
in Heller’s type specimens the proportion of the distance 
waka / 
