ri2 Records of the Indian Museum. [Vol. X, 



meet in a comparatively narrow setose apex, minutely pointed 

 in the middle and with two pairs of spines on either side, the 

 innermost much the longest. 



Lysntata chiltoni '■ differs in man}' respects from the well-known 

 L. seticaudata, Risso, the chief points being the length and dentition 

 of the rostrum, the form of the pterygostomian angle and 

 antennal scale, the length of the fused portion of the rami of the 

 upper antennular flagellum and the number of segments in the 

 carpus of the second peraeopods. Lysmata intermedia (Kingsley) 

 may be distinguished by the much greater length of the fused 

 portion of the antennule and by the comparatively short dactylus 

 of the first peraeopods. 



It is in Heller's Lysmata pusilla from the Red Sea that 

 L. chiltoni seems to find its nearest ally ; but in that species the 

 thicker ramus of the upper antennular flagellum is fused proxi- 

 mally with its fellow for only one third its length, there are only 

 four dorsal teeth on the rostrum and the two situated on the 

 ventral margin are more widely spaced. In the antennal scale, 

 moreover, the distal spine projects beyond the apex of the lamella. 



Four specimens were obtained at Meyer I. in the Kermadec 

 group. The type specimen is 27 mm. in length and is preserved 

 in the Canterbury Museum, New Zealand. 



Genus Hippolysmata, Stimpson. 



Carapace without supra-orbital, but with antennal spine : 

 antero-lateral (pterygostomian) spine present, reduced, or absent. 

 Lateral process of antennular peduncle anteriorly pointed. 

 Upper antennular flagellum uniramous. Mandible without incisor- 

 process or palp. Third maxillipede with exopod. Epipods (some- 

 times rudimentary), but no arthrobranchs at base of first four 

 peraeopods. Carpus of second peraeopods composed of many 

 (more than 10) segments. 



The only difference between this genus and Risso's Lysmata 

 is that in the latter the outer antennular flagellum is split and is 

 composed of two unequal rami which are fused basally. In Hippoly- 

 smata the flagellum is simple. The character does not seem a very 

 important one, but in m}^ experience is reliable' ; it is, however, 

 not improbable that further investigation will reveal such a 

 degree of gradation that two distinct genera can no longer be 

 recognized, and in this case all the species must take rank under 

 Lysmata. 



In two West Indian species, 'Hippolysmala moorei, Rathbun^ 

 and H. intermedia,^ Kingsley, the additional ramus is well developed 

 and they mu.st in consequence be transferred to Risso's genus. 



Two new species are here described from material in the 



1 I ha\e compared specimens with bot'n L. xehca/it/dfa and L. inter media. 



2 In addition to the species mentioned in this paper ' have examined Lysmatu 

 seficatidata, Kisso, Lysmata intermedia I Kingsley;, Hipj^olvsmntti californica. 

 Stimpson, and HippolysDiata iviirdemainii (Gibbesl. 



■^ Sec Rathlmn, Bull. T. S. l'"ish C'omm. for \qnn, X\, ii, pp. 115. \ih (i»)()_'). 



