igi5- J Fauna of the Chilka Lake : Crustacea Decapoda. 299 



The species is beautifully coloured in life. The entire animal is very closely 

 dotted with large maroon chromatophores, the gastric and hepatic regions sometimes 

 showing faintly through the carapace as reddish or greenish masses. The following 

 conspicuous patches of cream or lemon yellow occur: — a transverse bar, sometimes 

 merely a spot, situated dorsally in the middle of the carapace and another, always 

 well marked, at the posterior end of the carapace, occupying three-quarters of its 

 breadth in dorsal view ; a large spot on either side of the first abdominal somite ; a 

 similar spot on the second somite, with another lower down near the pleural margin, 

 and a large rnid-dorsal patch or transverse streak; a transverse band on the third 

 somite and a large pleural spot; a similar band on the fourth somite, rarely broken 

 into three patches. The fifth somite is maroon, rarely with a pair of small cream- 

 coloured spots posteriorly, and the posterior half of the sixth is entirely lemon yellow 

 or cream. The tip of the telson is sometimes cream, sometimes undifferentiated. 

 The antennules and antennal scales are often maroon, resembling the other parts of 

 the animal, or, in paler individuals, faintly mottled or wholly transparent. All the 

 maxillipedes and legs are transparent with a slight purplish tinge. The eggs are very 

 dull sage green. 



When walking A. polymorphus used only the last three pairs of legs, the first two 

 pairs being folded beneath the carapace. The antennules were held straight forwards 

 and the antennae at right angles. 



The species is described from twenty- seven specimens, eighteen females and nine 

 males. Of the latter five are of Form I, two of Form II and two of Form III. 

 All were obtained in the outer channel off Satpara and Barhampur I. on a muddy 

 bottom at depths ranging from 6 to 10 ft. Examples were caught both in March, 

 when the water was as salt as that of the Bay of Bengal near the lake, and in Sep- 

 tember when it was quite fresh. In the latter month only males of Form I and 

 non-ovigerous females were found, whereas in March the males obtained belonged 

 either to Form II or to Form III and three of the females were bearing eggs. 



Genus ALPHEUS, Fabricius. 

 Alpheus crassimanus, Heller. 



1865. Alpheus crassimanus, Heller, Crust. ' Nov ara ''-Reise, p. 107, pi. x, fig. 2. 

 1888. Alpheus crassimanus, Bate, Rep. ' Challenger ' Macrura. p. 554, pi. xcix, fig. 2. 



1898. Alpheus lobidens, Coutière, Notes Ley den Mus., xix, p. 199. 



1899. Alpheus crassimanus , Coutière, Ann. Sei. nat., Zool. (8), ix, p. 239, text-fig. 293. 



1902. Alpheus crassimanus, de Man. Abhindl. Senckenb. Ges. Frankfurt, XXV, p. 880, pi. xxvii, 



fig. 62. 

 I9ir. Alpheus crassimanus, de Man, Rep. ' Siboga' Decap., II, Alpheidae, p. 417. 



The characters on which I have relied for the identification of this species are 

 the following: — 



The rostrum reaches to a point midway between the margins of the orbital hoods 

 and the end of the first antennular segment. It extends backwards nearly to the 



