3o8 



Records of the Jniian Miiscii 



III. 



[Vol. XXII, 



specimen of this scarce species obtained at Pnlo Adaiig. about loo 

 miles north-west of Penanp;. 



The characters given in 19x3 for separating this species from 

 0. scyllarus were derived from the published figures and descrip- 

 tions and were not based on actual comparison of specimens. 

 They may be amended as follows : — 



0. scyllitrus (Linn.). 



Rostrum broadly corditorm ; apex 

 pointed and lateral margins strongly 

 convex. 



Eyes small, reaching a litile beyond 

 base of penultimate segment of anten- 

 nular peduncle and to base of ultimate 

 segment of antennal peduncle ; greatest 

 breadth of cornea about one-fifth length 



of 



carapace 



Second segment of antennular ped- 

 iipcle about 3 times as long as wide. 



DactyUis of raptori.al claw strongly 

 inflated at base. 



.\ carina present on last abdominal 

 somite between submedians and inter- 

 mediates. 



.Median crest of telson not remark- 

 ably elevated, with two submedian 

 carinaeon either side ; submedian spines 

 of telson broadly expanded, with small 

 movable tips. 



Basal segment of outer uropod nearly 

 twice as long as ultimate segment, with 

 II or 12 movable spines on ouler edge. 



(). cultrijer (White). 



Rostrum quadrangular with conver- 

 gent sides ; apex broadly rounded and 

 lateral margins slightly concave. 



R)es larger, reaching beyond base of 

 ultimate segment of antennular peil- 

 uncle and to end of ultimate segment 

 of antennal peduncle ; greatest breadth 

 of cornea about one-third length nf 

 carapace. 



Second segment of antennular ped- 

 uncle scarcely li times as long as wide. 



Dactylus of raptorial claw slighlly 

 inflated at base. 



No c irina on last abdominal somite 

 between submedians and intermedia'es. 



Median crest of telson remarkably 

 elevated, with only a single submedian 

 carina on either side ; submedian spines 

 of telson not expanded, with large mov- 

 able tips. 



Basal segment of outer uropod shorter 

 than ultimate segment with 8 or t) mov- 

 able spines on outer edge. 



The specimen we have examined is a female, 55 mm. in 

 length. The median crest of the telson is apparently less elevated 

 than in the larger individual figured by White. Its height at the 

 distal eird is, however, nearly one c^uarter the basal breadth of 

 the telson, whereas the proportion is less than one eighth in a 

 much larger specimen of 0. scyllarus. 



In the specimens hitherto e.Kamined only two teeth have been 

 foimd on the inner edge of the raptorial dact^'lus In our speci- 

 men, however, three occur on each side. The knowledge that 

 these teeth vary in number leads us to think that Pocock was 

 perhaps right in suggesting that his 0. carinifcr was based on a 

 young example of 0. cultrijer. The single specimen that he 

 described under the former name was only 24 mm. in length and 

 all the characters that distinguish it from the related species, 

 except the number of dactylar teeth, may be due to immaturity. 



0. Lulirijcr has hitherto been known from only three specimens : 

 from China (White), from Kelantan in the G. of Siam (Manchester) 

 and from 27 fms. in the western Java Sea (Sunier). Pocock's 

 specimen of 0. carinifer was obtained in 24 fms. on the Holothuria 

 Bank, China Seas. 



1 This character probably varies somewhat with age, the eye being proportion- 

 ately largest in young specimens. 



