if)22.] S. Kemp : Notes on Crustacea Decapoda. 129 



As in the two preceding species the mandibular palp is com- 

 posed of two segments, but it differs in that the distal segment 

 is very much shorter than the proximal. This is perhaps merely 

 an abnormality and only one mandible was examined. 



The single specimen is about 15 mm. in length In life it 

 was perfectly transparent except for a few small red chromato- 

 phores on the carpus and chela of the second legs. 



P. lata is readily distinguished from related species by the 

 broad apex and short terminal spine of the antennal scale and by 

 the absence of the spine at the distal end of the merus of the 

 second peraeopods. 



( 401 i. Port Blair. Andamans. S. Kemp, Feb., 1921. One, Type. 



The specimen was found in a rock-pool at Aberdeen at low 

 water. 



Palaemonella tenuipes Dana. 



1852. Palaemonella tenuipes, Dana, U. S. Explor. Kxped., Crust '. I, p. 

 582 pi. xxxviii, figs. $a-ti. 



1898. Palaemonella tridentata, Borradaile, Proc. Zool. Soc. London, 



p. 1007, pi. Ixiv, figs. 8a-c. 



1899. Palaemonella trident at a, Nobili, Ann. Mus. civ. Genova (2) 



XX, p. 235. 

 1906. Palaemonella tenuipes var. (ami. sp. ?), Nobili, Ann. Sci. nat., 



Zool. (9) IV, p. 70. 

 1917. Palaemonella tenuipes and tridentata, Borradaile, Trans. Linn. 



Soc. (2) Zool. XVII, pp. 323, 358. 

 192 1. Palaemonella tenuipes, Tattersall, Journ. Linn. Soc, Zool. 



XXXIV, p. 383. 

 ' 192 1. Palaemonella tenuipes, Balss, K. Svenska Vet.-Akad. Hand/. 



I. XI, no. 10. p. 14. 



I have examined a single example of this species obtained at 

 Peros Banhos in the Chagos Archipelago. It differs conspicuously 

 form all other species of the genus that I have seen in the posses- 

 sion of a large subterminal spine on the upper and inner aspect 

 of the carpus of the second peraeopod in addition to one or 

 two small angular projections on the actual distal margin of the 

 segment. The subterminal spine is clearly shown in Dana's 

 figure. 



In determining the specimen in the collection I have derived 

 much assistance from the notes which Tattersall has recently pub- 

 lished. I have no doubt that my specimen is specifically iden- 

 tical with those that he examined and I accept his view that they 

 should be referred to Dana's P. tenuipes. The identification pre- 

 supposes a considerable amount of error in Dana's figures, but we 

 have ample evidence that these are not to be trusted in the finer 

 detail now necessary for systematic work on the Macrura. 



Tattersall remarks that Borradaile's P. tridentata is closely 

 allied to P. tenuipes and is doubtfully distinct. I go further and 

 regard the former as a synonym of the latter. 



The specimen examined was obtained by Prof. Stanley 

 Gardiner's expedition and was determined by Borradaile as P. 



