494 Records of the Indian Museum. [Vol. XXIV, 



pleopods but none of the others. His description, however, agrees 

 with that of Hansen, in stating that the first, second, third and fifth 

 pairs of pleopods in the male are biramous with exopodite and endo- 

 podite. In spite of this anomalous form of the pleopods, Colosi 

 places Lycomysis spinicauda in the tribe Mysini of the subfamily 

 Mysinae. But if the descriptions of Hansen and Colosi are correct 

 this position for the species cannot be maintained, for in the 

 Mysini at least the first and second and inmost cases the fifth pair of 

 pleopods of the male are simple unjointed plates as in the females 

 of Mysidae generally, without any definite indication of a separate 

 endopod and exopod. 



In the meantime Zimmer (1915 (3)) described a second species 

 of Lycomysis, L. pusilla. It is evident that Zimmer was puzzled b)' 

 Hansen's description of the pleopods in his species for Zimmer's new 

 species is founded entirely on the characters of the pleopods of the 

 male, the author stating that in all other characters his species was 

 identical with L. spinicauda. Zimmer (1915 (3), p. 175) describes 

 the pleopods of the male in L. pusilla as follows: — "Diepaare 1, 2, 

 3 und 5 rudimentar, wahrend 4 einene eingliederigen Innen- und 

 stark verlangerten Aussenast besitzt " and later (p. 177) he states 

 that the pleopods 1, 2, 3 and 5 of the male are as in the female. 

 He gives a figure of the first pleopod of the female which shows 

 this appendage as a simple unjointed plate, somewhat bilobed at 

 the apex, each of the lobes bearing setae. His description of the 

 pleopods of the female states that in the first three pairs the two 

 lobes are more or less equal in size, but in the last two pairs the 

 inner lobe is much longer than the outer. The fourth pair of pleo- 

 pods of the male have an endopodite which corresponds with the 

 female pleopod in shape and a very elongate exopod of three joints 

 terminated by a single long plumose seta. 



Zimmer's species is clearly referable to the Tribe Mysini and 

 the present specimen agrees absolute^ with his description and 

 figures in the matter of the pleopods of the male. 



Colosi (1920) gives some further notes on L. spinicauda, 

 Hansen, and compares it with L. pusilla, Zimmer. His description 

 of the pleopods of the male of L. spinicauda is substantially as in 

 his previous paper and he points out that the two species are 

 distinguished not only by the pleopods but by the characters of 

 the mandibular palp, the terminal joint of which is longer and nar- 

 rower in L. pusilla than in L. spinicauda and the teeth on the 

 margin of the second joint less well marked in the former than in 

 the latter. I regard these latter differences between the two 

 species as of no moment and due mainly to the fact that Zimmer's 

 figure is taken from a somewhat more oblique point of view than 

 Colosi's. 



But the differences in the pleopods of the male are more 

 puzzling. It is almost inconceivable that two species so essenti- 

 ally alike in all other details that female specimens could not be 

 distinguished one from another, should differ so profoundly in the 

 structure of the male pleopods that adult males should require to 



