1901.] OBUSTAOBA OF THE " SKEAT EXPEDITION." 57 L 



part of it which lies on the first of these four segments being 

 grooved on its upper surface, those parts which lie on the last 

 three ending each in a very distinct tooth. Secondly, there are 

 only three lateral spines on the telson, of which the posterior two 

 are nearly three times as long as the first. 



84. PBST2EUS canaliculars Olivier, var. '.' (Plate XXXIV. 

 fig. 5.) 



Perueus canaliculate.*,, Oliv. Encycl. Ale'th. viii. p. 660 (I807)j Sp. 



Bate. ' Challenger ' Macrura, p. 243, pi. xxxii. fig. 1 (1888). 



hoc. Pulau Bidan, Penang. 



Two females and a male. Length : cJ 58 mm., 2 59 mm., 2 

 50'5 mm. 



The form of the petasma agrees with that of the species, but 

 the form of the thelycum differs from that of the species and of 

 the varieties figured by Spence Bate (t. c. pi. xxxii. figs. 3 and 4). 

 The thelycum proper is nearly like that of the species, but there 

 is an additional plate between the 4th pair of legs and no plate 

 between the 3rd pair (cf. fig. 5). I have no!" given a distinct name 

 to this form, as it has seemed to me that too little is known 

 about the thelycum, aud its possibly seasonal varieties within 

 the same species, to justify the founding of a new variety on this 

 character. 



The telson in these specimens is armed laterally with three 

 teeth, as in P. caramote Pusso, and in the varieties japo ulcus and 

 auetralieims Spence Bate ; but the absence of a strong spine on the 

 3rd pair of legs distinguishes it from P. caramote, and the form of 

 Ihe thelycum from .Spence Bate's varieties. 



35, Pl>'.LI'S BBEYIOOBNIS M.-Edw. 



Penceut brevicomie, M.-Edw. Hist. Nat. Crust, ii. p. 417(1637); 

 Sp. Bate, Ann. Mag. Xat. Hist. (5) viii. p. 180, pi. xi. fig. '2 

 (1881). 



Loe. Patani. A female : length 70 mm. 



86. PXBJBOB sp. ? ( Plate XXXIV. fig. 7.) 



Loc. Patani. 



\ male, of 56 mm. length, whose specific position I cannot 

 determine with any certainty: tor, though agreeing remarkably 

 with the last species {P. brevicornit), it still presents two features 

 wliich would seem sufficient to separate it from the latter. Its 

 era! form and the shape of the petasma, which agrees with the 

 tigure given bj Speuce Bate of thai of I', brevicomis (I.e. supra). 

 lod mi- at Hrul to regard it as belonging to that species, hut a closer 

 examination showed the following notable distinctions: — (a) the 

 rostrum barely reaches the tips ot the i'\rs. instead of being JU8< 

 a little longer than these, ami it is less raised in its proximal 



portion ovur tin- bate of the eye ; (At the peduncles of the anten- 

 nules peach t" the ends "i the antenna) scales, ami their ingellu 



