I9I5-] 



Fauna of the Chilka Lake : Crustacea Decapoda. 



265 



Genus PALAEMON, Fabricius. 

 Palaemon lamarrei, Milne-Edwards. 



1908. Palaemon (Eupalaemon) lamarrei, de Man, Rec. Ind. Mus., II, p. 222, pi. xix, fig. 4. 



This species is represented in our collection by numerous specimens found at 

 Rambha in February and at Barkul in March 1914. All the larger examples are 

 females and a great number bear eggs. 



The measurements (in mm.) of four specimens are as follows 1 : — 





S 



la 

 +-> 

 O 



Length of 

 carapace. 



Length of 

 chelipede. 



Chelipede (2nd leg) : length of 



B 

 



in 

 1— ( 



en 



«5 



1- 

 



à 



cd 



«5 



3 



-M 

 O 



ca 



Q 



9 



? 

 5 



58 



54 

 50 

 44 



I3'4 



124 



11 



9-6 



25-5 



22'6 

 21 6 



i9'o 



5-0 

 4'5 

 4'4 

 4-1 



57 

 51 

 5'0 

 4'3 



8-o 



7-1 

 6-9 



60 



3'4 



2-6 



2-3 

 1-9 



2-6 



2'I 



2'0 

 17 



It will be noticed that there is some difference between these figures and those 

 given by de Man for younger specimens; the carpus, in particular, though still 

 decidedly longer than the chela, is proportionately shorter. 



The rostrum, in adult females, reaches only to the apex of the antennal scale, or 

 a little beyond it. In other respects the specimens agree closely with de Man's 

 description. 



Henderson and Matthai have pointed out % that the eggs in this species are very 

 large and by hatching experiments have succeeded in proving that development is 

 direct and without metamorphosis. In the Chilka specimens eyed eggs average 1*5 

 mm. in length by 11 mm. in breadth, measurements which differ somewhat from 

 those obtained by the above-mentioned authors from specimens found near Madras. 



Palaemon lamarrei, originally described by Milne-Edwards from the coasts of 

 Bengal, is common in the Gangetic Delta in fresh or slightly brackish water and, as 

 noticed above, has been found near Madras. De Man (loc. cit.) has pointed out that 



1 In this table, and in the measurements given on succeeding pages, the total length is taken from 

 the tip of the rostrum to the apex of the telson and the length of the carapace from the back of the 

 orbit to the mid-dorsal point at its posterior end. The chelipede is measured from the basipodite 

 (which forms a convenient point of application for a pair of callipers) to the tip of the chela. In. the 

 case of individual segments the measurements represent the greatest length of each segment. The 

 instrument used in taking all measurements under 100 mm. is a pair of callipers fitted with a dial which 

 gives direct readings to 'I mm. 



2 Henderson and Matthai, Rec. Inà. Mus., V, p. 301 (1910). 



