1901.] CUUSTACEA OF THE " SKEAT EXPEDITION." 535 



smaller areas within the broad areas, and still smaller areas 

 (habitats) within these, peculiar to that species ; and it is these 

 smallest, quite local, areas to which attention needs to be directed 

 in order to elucidate the causes of confinement to a special habitat, 

 or, on the other hand, to answer the question : Does tlie same 

 species adopt the same habitat in different distributional areas? 

 1 have already noted (P. Z. S, 1900, " On Crustaceans from 

 Singapore and Malacca") how certain Leucosiids were obtained 

 there from mud which had been found by Adams and "White 

 (' Samarang ' Crustacea) in the China Sea on a clean sandy or 

 rocky bottom. Such a difference of habitat is most striking and 

 seems tome to require explanation: this explanation, how e\er, 

 can hardly be arrived at until more data of a similar kind are 

 forthcoming. 



I have taken my measurements of length and breadth in a 

 similar way to those given in my paper already cited (vide P. Z. S. 

 1900, p. 720). In those cases, however, in which no supraocular 

 or prseocular spine is present (Macrura &c.) I have measured from 

 the upper internal angle of the orbit. The units are in milli- 

 metres, and the first figure given in each case stands for the breadth. 



I. Genus Doclea Leach. 



1. Doclea canalieera Stimpson. 



Doclea canaJifera, Stimpson, Proc. Ac. Nat. Sci. Philad. p. 217 

 (1857) ; Alcocli, Journ. As. Soc. Beug. Ixiv. 2, p. 228 (1896). 



Loc. Pulau Bidan, Penang. 



A single male ; all the legs absent. 



This individual agrees closely with Major Alcock's description; 

 but there are two small points which ma}^ be noticed in connection 

 with it, as neither Major Alcock nor Stimpson make any mention 

 of them. On the gastric region are " some minute tubercles 

 followed by a spine." The number of the tubercles here in front 

 of the spine is five, of which the tAvo anterior lie transversely close 

 to each other, exactly at the level of the back of the orbits, each 

 tubercle corresponding to one of the posteriorly coalesced rostral 

 spines, the distinction of the two being still indicated at this level. 



Besides the oblique line of tubercles on the hepatic region, 

 moreover, there may be seen three more in front of this line, one 

 in front of, and the other two (transversely placed) behind, the 

 level of the first lateral spine. 



Dim. 23 X 25-5. 



II. Genus Schizopheys White. 



2. Schizopheys aspbra M.-Edw. 



Mithrax aspera, M.-Edw. Hist. Nat. Crust, i. p. 320 (1834). 

 Dione affinis, de Haan, Crust. Japon. p. 94, pi. xxii, fig. 4 (1839). 

 Schizoplirys aspera, A. M.-Edw. Nouv. Arch. Mus. viii. p. 231, 

 pi. X. fig. 1 (1872); Hasw. Cat. Austr. Crust, p. 22 (1881). 

 Loc. Pulau Bidau, Penang. 

 K female. 



