1922.] W. M. Tattersali, : Indian Mysidacca. 495 



be placed in separate subfamilies at least. I can only suppose 

 that Hansen and Colosi are in error in describing the first, second, 

 third and fifth pleopods in the males of L. spinicauda as biramous, 

 with endopodite and exopodite defined. I give herewith a figure 

 of the third, fourth and fifth pleopods of my specimen. The 

 outer lobe (seitenlobus) is remarkably well developed in all the 

 pleopods and in the first three is as long as the inner lobe (haup- 

 teile). Zimmer makes the same observation. In the fourth and 

 fifth pair the inner lobe is much the longer, in the fifth pair longer 

 than in the fourth. At first sight the appendages look biramous 

 and it is only when dissected and examined under the high power 

 of the microscope that they are found to be simple unjointed 

 plates of the type usual in the females of Mysidae except that 

 the outer (side lobe) is unusually well developed. If we suppose 

 the words endopod and exopod in Hansen's statements to be 

 replaced by inner lobe and outer lobe, Hansen's description of 

 L. spinicauda applies equally well to L. pusilla. In fact, if my 

 suggestion is correct the two species should be united under the 

 name spinicauda and it is in this light that I have regarded them 

 here. 



Distribution: — L pusilla was recorded by Zimmer from a 

 collection made during a voyage from Ceylon to New Guinea. L. 

 spinicauda is known from the waters of the East Indian Archipe- 

 lago (Hansen) and the China Sea (Colosi). The distribution of 

 the two forms is therefore not inconsistent with their suggested 

 specific identity. 



Tribe Heteromysini. 



Genus Heteromysis, S. I. Smith. 



Syn. Chiromysis G. O. Sars. 



Gnathomysis Bonnier and Perez. 



Through the kindness of Professor C. Perez, I have been per- 

 mitted to see a series of unpublished drawings made by the late 

 Dr. Jules Bonnier to illustrate the general form and the structure 

 of the appendages of Gnathomysis gerlachei (Bonnier and Perez, 

 C. R. Acad. Sci. Paris, T. 134, p. 117-119, 1902), a preliminary 

 description only of which, without figures, has so far appeared. 

 1 have not been able to examine the specimens from which the 

 drawings were made but there is no doubt in my mind, after 

 studying the drawings sent to me by Professor Perez, that 

 Gnathomysis gerlachei is identical with Chiromysis harpax Hilgen- 

 dorf. The genus Gnathomysis is therefore a synonym of Chiro- 

 mysis G. O. Sars, which in turn must give way to the earlier 

 Heteromysis S. I. Smith. 



Heteromysis harpax was described by Hilgendorf in 1879 in 

 very summary fashion. Kossmann (1880) redescribed the species 

 from examples collected in the Red Sea and figured the append- 

 ages in some detail. It is difficult to be sure that Kossmann des- 



