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



respect leads me to believe that the varietal name cannot be retained. The largest 

 examples from the Chilka Lake do not exceed 120 mm. in length and, in them, the 

 rostrum exceeds the tip of the antennal scale by one-fourth or one-fifth of its length. 



In life the general colour is translucent whitish, with numerous small brownish, 

 greyish, or greenish chromatophores scattered over the carapace and abdomen. The 

 upper half of the rostrum, base of the eyestalks, dorsal carinae of the last three ab- 

 dominal somites, telson and uropods are deeply pigmented with maroon and dull brown 

 chromatophores. The antennae and the terminal parts of the exopods of the second 

 and third maxillipedes are pinkish ; the tips of both uropods and the external 

 margins of the outer pair are pinkish-red with similarly coloured setae. The anten- 

 nular flagella are lemon yellow, banded and dotted with maroon. 



In the Chilka Lake P. indicus is more abundant than P. carinatus. It is caught 

 in large numbers by the Uriya fishermen and occurs at all seasons of the year both in 

 the main area and in the outer channel. In the latter region a young form was 

 taken in abundance which must, I believe, be referred to this species. In life it is 

 semitransparent, sparsely pigmented with brown; the rostrum is very long, toothed 

 both above and below. It does not present the attenuated appearance of late post- 

 larval individuals of the preceding species. Unfortunately no specimens correspond- 

 ing to the pelagic stage of the latter were obtained. 



P. indicus appears to have a distribution extending from E. Africa and the Red 

 Sea to China, but not reaching Japan. 



Genus PENAEOPSIS, Bate. 



1881. Penaeopsis (A. Milne- Edwards, MS.), Bate, Ann. Mag. Nat. Hist (5), VIII, p. 182. 



1891. Metapenaeus, Wood-Mason, Ann. Mag. Nat. Hist. (6), VIII, p. 271. 



1906. Metapeneus, Alcock, Cat. Indian Decap. Crust., Ill, i, p. 16. 



jqog. Penaeopsis, A. Milne-Edwards and Bouvier, Mem. Mus. Comp. Zool. Harvard, XXVII, 



p. 220. 

 1911. Penaeopsis, de Man, Decap. ' Siboga' Exped., I, Penaeidae, p. 53. 



Bate's description of this genus is worthless; but it is clear from the work of 

 A. Milne-Edwards and Bouviei (1909) that P. serratus, the type species of the genus, 

 is indistinguishable generically from the forms on which Wood-Mason based his 

 Metapenaeus. The latter name must consequently lapse. 



Three species of this genus occur in the Chilka Lake. Two of them, P. mono- 

 ceros (Fabr.) and P. dobsoni (Miers) are abundant and are found throughout the year 

 both in the main area and in the outer channel. The third, P. affinis (A. M.-Edw.). is 

 apparently scarcer ; though not found in the outer channel there can be little doubt 

 that it occurs there, for specimens were obtained at all seasons in the main area and 

 numerous examples were recorded by Alcock from the ' Investigator ' dredgings on 

 the Orissa coast. All three forms are evidently able to exist in water of specific 

 gravity varying from 1000 to 1-0265; but I think it improbable that any of them 

 breed in the lake. Species of this genus were more frequently caught in our bottom 

 nets in the middle of the main area than those of Penaeus. 



