I9T5-] 



F aima of the Chilka Lake : Crustacea Decapoda. 



247 



Fig. ig. — Leipocten sordidulum, 

 gen. et sp. nov. 



Fourth peraeopod viewed obliquely from below. 



extends back proximally to a point not far from the articulation of the ischium, 



then turns across the inferior face of the segment in the form of a series of slender 



teeth with blunt tips and is continued obliquely 



outwards to the antero-inferior angle of the 



mero-carpal joint. In the last part of their 



course the spinules are widely separated and 



are reduced to small tubercles; but, close to 



the carpus, they are more closely set and form 



a finely serrate crest. The spinules are better 



developed in the female than in the male; seen 



from below they present a (J-shaped figure, 



the upper extremities of the U being situated on either side of the mero-carpal joint. 



The carpus and propodus are short and swollen and bear a few blunt teeth distally. 



The dactylus is conical and slightly curved. 



The form of the abdomen in the male and female is shown in text-figs. 20a 

 and 206. 



Except for the chelipedes of the male the entire upper surface of the animal is 

 densely clothed with a fine woolly hair 

 that retains large quantities of mud 

 and can only be removed with consi- 

 derable difficulty. Interspersed among 

 the hairs are numerous large black 

 bristles. 



The carapace of the largest female 

 is 8 - 1 mm. in breadth, that of the 

 largest male 6-5 mm. 



Of this curious and variable species 

 five females only were obtained in the 

 Chilka Lake. All were found hiding 

 among shells on the oyster-bed in the 

 outer channel opposite Manikpatna. 

 Two individuals were taken in March 



in water as salt as that of the Bay of Bengal in the vicinity of the lake (sp. gr. 

 1-0265), one in September in water that was quite fresh and two in December in 

 water of specific gravity 1-0125. O ne °f the specimens found on the last of these 

 occasions is ovigerous. 



A fine series of specimens, consisting of ten males and twenty-seven females, 

 mostly ovigerous, was obtained by Dr. Annandale in the Ennur backwater near 

 Madras in January 1915. They were found in cavities in latérite blocks forming 

 a sea-wall, submerged at high water. The specific gravity of the water was 

 1-0025. 



The types of the species bear the numbers 9163-4/10 in the Museum register. 







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a. b. 



Fig. 20. —Leipocten sordidulum, gen. et sp. nov. 

 a. Abdomen of male. b. Abdomen of female. 



