3i8 



Memoirs of the Indian Museum. 



[Vol. V, 



de Man's identification of P. carinatus is, however, open to criticism, for Dana 

 neither figures nor mentions the subhepatic crest of the carapace. It is most unfortu- 

 nate that the correct name of this species, the common prawn of the Calcutta markets, 

 must still remain uncertain. 



Adults of the species are deeply pigmented with a tint varying from olive green to 

 deep bluish-grey, usually the latter in large examples, with darker transverse bars on 

 the abdomen. The colouring is sometimes almost as bright as in Stebbing's figure 1 

 of P. caeruleus; the bars have the same distribution, but are always more conspicu- 

 ous in life. The outer surface of the protopodite of each pleopod is invariably 

 bright lemon yellow, a distinctive feature not shown in Stebbing's figure and hardly 

 indicated in that which Kishinouye has given of P. monodon* (a synomym of P. 



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^£^ 



carinatus). 



Fig. 36. — Penaeus carinatus, Dana (de Man). 



a. Pelagic post-larval stage. 



b. Rostrum, eyes, etc. of a somewhat older specimen. 



In young specimens some 2 or 3 inches in length the colour is pale grey with a 

 dark green mottling among which the transverse bars of the abdomen are only 

 detected with difficulty. The yellow patches on the pleopods are absent. 



1 Stebbing, Marine Invest. S. Africa, IV, pi. xxi bis (1905). P. caeruleus, according to Stebbing, 

 does not possess an exopod at the base of the last legs; but de Man has found this appendage in one of 

 the type specimens and queries P. caeruleus as a synonym of de Haan' s semisulcatus. I have never 

 seen a fresh specimen of the latter and consequently have no knowledge of its colouration. Stebbing 

 notes that the integument of P. caeruleus " has the property of retaining for years in preservative 

 media (spirit and formalin) the fascinating blue colour to which the specific name refers." This is 

 certainly not the case with P. carinatus: specimens turn red after only a day's immersion in alcohol. 



" z Kishinouye, Journ. Fish. Bureau Tokyo, VIII, pi. ii, fig. 1 (1900). The figure appears to have 

 been coloured from a preserved specimen. 



