1916.] S. Kemp : Notes on Crustacea Decapoda. 395 



The abdominal somites are not carinate dorsally. The third 

 is very strongly humped and the sixth, which is but little longer 

 than the fifth, is produced to a rounded prominence in the middle 

 of its posterior margin. The endopod of the last four pairs of 

 pleopods bears an appendix interna and is enormously expanded 

 in the female (text-fig. 2k) ; in the male it is not broader than the 

 exopod. The margins of l^oth rami bear long setae. 



The telson (text-fig. 2/) is nearly twice the length of the sixth 

 somite and is feebh^ sulcate above. It bears two or three pairs of 

 small dorso-lateral spines and terminates in a broad, almost trun- 

 cate apex (text-fig. 2in) armed with three pairs of spines, the 

 innermost the longest, about equal to the breadth of the apex, 

 and the outermost m.uch the shortest. Between the innermost 

 pair of spines are two minute splnules, while a similar spinule 

 occurs on either side between the bases of these spines and those 

 of the intermediate pair. The outer uropods do not reach the 

 apex of the telson ; they are shorter than those of the inner pairs 

 and are rather more than two and a half times as long as wide. 



The long setae that have been described above as plumose 

 differ considerably from those to which this term is generally ap- 

 plied, for the plumes have not the form of ver^^ fine microscopic 

 hairs, but are comparatively short and blunt processes from the 

 main axis of the seta. 



The largest specimen obtained, an egg-bearing female, is barely 

 9 mm. in total length; other ovigerous individuals do not exceed 

 7 mm. 



This curious little species was found at Port Blair near Ross 

 I., living among weeds in water from 2 to 4 fathoms in depth. 

 We found it impossible to obtain specimens at all freely by the 

 usual methods, but if the contents of the net were immediately 

 transferred to a bucket of sea-water, individuals were sometimes 

 found swimming at the surface and alighting on floating fragments 

 of weed. 



The illustration on Plate xxxvi, which is based on sketches 

 made from living specimens, will give an idea of the peculiar atti- 

 tude that the species adopts. The abdomen is strongly flexed near 

 its junction with the cephalothorax, so much so that the third 

 segment as a rule almost touches the carapace, and the antennules 

 are bent upwards and backwards. In this attitude, and with the 

 help of the long plumose setae that the species possesses,' Phyco- 

 caris bears the most extraordinarily close resemblance to small 

 tufts of algae that are plentiful on the weeds : it was only after 

 considerable experience that we were able to distinguish the one 

 from the other. The resemblance, which is undoubtedly protec- 

 tive, is further enhanced by the colour. The tufts of algae vary 

 in shade and are sometimes dull olive-yellow and sometimes 

 almost black. Two colour varieties of the prawn, corresponding 



^ These setae are very easily broken off in preserved specimens and are in lite 

 more numerous and longer than is shown in the figure. 



