268 Memoirs of the Indian Museum. [Vol,. V, 



palm and dactylus are approximately as 18, 18^-, 26, 17 and 15. The ischium, as 

 Henderson and Matthai have shown, is as a rule proportionately longer in young (but 

 not necessarily non-adult) Palaemonidae, than in full grown individuals. If allow- 

 ance be made for this point it will be seen that the proportions are not strikingly 

 different from those of large females. The segments bear small spinules precisely 

 as in the large specimens. 



A notable difference exists in the armature of the telson tip. In the Satpara 

 specimens the inner pair of terminal spinules project far beyond the apex, whereas in 

 large P. malcolmsoni they fall considerably short of it. 



Whether the series from Satpara is correctly referred to P. malcolmsoni or not — 

 and I am extremely doubtful of the accuracy of the determination — it is clear that 

 it does not include any fully developed males and is therefore inadequate for a com- 

 plete specific description. If the specimens are not young P. malcolmsoni they cer- 

 tainly cannot be identified with any other form known from Indian waters. 



It will be noticed that in the specimens from Pondicherry, referred by Nobili to 

 Heller's P. danae l and regarded by Henderson and Matthai as young P. malcolmsoni, 

 there are fewer teeth on the lower border of the rostrum and no spinules on the seg- 

 ments of the second peraeopods. 



The carapace of living examples from Satpara was dotted with chromatophores 

 which formed definite spots laterally and an indefinite longitudinal dorsal streak. 

 There was a conspicuous dorsal patch of white in the posterior part of the third ab- 

 dominal somite and the legs were banded with maroon, with all the joints orange yellow 

 and the dactyli of the last three pairs clear red. The chela of the second peraeopods 

 and caudal fin were mottled with maroon and yellow pigment and the edges of the 

 abdominal pleura were brown. 



In the case of the large females from Barkul the legs were not banded, but had a 

 purplish tinge. The margins of the abdominal pleura were usually bordered with 

 pure white, but those of the last two segments were in some cases brown. There 

 was no white patch on the third abdominal somite. The eggs in both cases were 

 of an olivaceous tint. 



The large females from Barkul were obtained when the water was quite fresh. 

 The fact that, among numerous specimens examined, no large males were to be found, 

 suggests that the females, as with P. lamarrei, may migrate to the lake when their 

 eggs are ready to hatch. 



The specimens of doubtful identity, obtained at Satpara, were found in water 

 as salt as that of the Bay of Bengal near the mouth of the lake. 



Palaemon rudis, Heller. 



1910, Palaemon ruais, Henderson and Matthai, Rec. Ind. Mus., V, p. 291, pi. xvii, figs. $a — h. 

 Palaemon rudis is the commonest species of its genus in the Chilka Lake and is 

 represented in our collection by a large number of specimens both young and adult. 



1 Nobili, Boll. Mus. Torino, XVIII, No. 452, p. 7 (1903). 



