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



The antennular peduncle reaches to less than half the length 

 of the antennal scale. Its basal segment is elongate (pi. Ill, 

 fig. 4), about three times as long as broad, and its lateral process 

 is anteriorly rounded and feebly bilobed. The second segment 

 is, in the female, longer than broad. The antennal scale (pi. Ill, 

 fig. 5) is very sharply pointed anteriorly and is more than six 

 times as long as broad. 



The third maxillipedes reach to the base of the antennal scale, 

 the peraeopods of the second pair to the middle of the eye, those 

 of the fifth pair extending scarcely further forwards. Of the 

 three segments composing the carpus of the second peraeopods 

 the middle one is the longest and the third the shortest. The 

 middle segment is about one and a half times the length of the 

 first and the first is one and a third, or rather more than one and 

 a third times the length of the third : there is a little variation in 

 the precise measurement of these segments. The dactyli of the 

 last three peraeopods terminate in sharp curved spines : there are 

 a few other spines on the po.sterior margin, the ultimate being 

 large and placed close to the terminal spine, giving the apex a 

 biunguiculate appearance (pi. Ill, fig. 6). Epipods are present 

 at the base of the first four pairs of legs. 



The sixth abdominal somite is fully one and three quarters 

 the length of the fifth. The telson in S. Indian specimens bears 

 only two pairs of dorso-lateral spinules in addition to those at 

 the apex, not three as Nobili has stated. 



The male is very different in appearance to the female. It 

 is much more slender in build and the rostrum seldom bears more 

 than one tooth on either margin near the apex. The antennular 

 peduncle is shorter than in the other sex, but the upper flagellum 

 is stouter and very much longer. In the female the flagellum 

 does not nearly reach the apex of the antennal scale, whereas in the 

 male it extends beyond that point by almost half its length. 



The colour of living specimens is ver}^ variable. As a rule 

 the}^ are of a uniform dull green, but olive, brown and brownish 

 red specimens are frequent. 



Latreutes pygmaeus has exceedingly close affinities with 

 L. ensifer^ Milne Edwards, the type species of the genus. I 

 have compared South Indian specimens of the former species with 

 examples of the latter obtained in the Sargasso Sea. The 

 Atlantic form is slightly more robust in build, the rostrum is more 

 strongly concave above and the teeth are more closely restricted 

 to the apex. The legs are a little longer, the second pair reach- 

 ing the ends of the eyes, the antennal scale is proportionately a 

 trifle broader and the sixth abdominal somite is shorter and a 

 little less slender. The second segment of the antennular peduncle 

 is about as broad as long in the female Probably the best distinc- 

 tion between the two forms rests in the number of epipods at the 

 base of the legs; in L. pygmaeus they are found on the first four 

 pairs, while in L. ensifer thev occur onlv on the first three. 



