PALAEMON CARCINUS. 165 



NOTE XLI. 



ON SOME SPECIES OE THE GENUS PALAEMON 

 FABR. WITH DESCRIPTIONS OF TWO NEW FORMS. 



BY 



Dr. J. G. DE MAN. 



May 1879. 



P alaemon carcinus Fabr. 



Milne Edwards , Hist, natur. des crust, t. II , p, 395. — 

 Von Martens , Ueber einige Ost-asiatiscbe Siisswassertliiere , 

 in "Archiv fur Naturgescbichte," 1868, p. 34. 



There are specimens of this beautiful species in the 

 Museum collection from Siam , Java , Celebes (Makassar) 

 and Borneo. Always, at every age, the first pair of legs 

 are longer than the scale of the external antennae: in 

 very large adult specimens they project with half of the 

 wrist (carpopodite) beyond the antennal scale, in young 

 and very young specimens only with the hands (cheli- 

 pedes). In adult specimens the carpopodite of the second 

 pair of legs is as long as the palm , but it is comparatively 

 longer in young specimens. Thus in a young male spe- 

 cimen that has a length of 65 millimetres (the distance 

 between tip of beak and end of terminal segment) , the 

 carpopodite of the second pair of legs measures 9 mm., 

 the palm 4^/2 mm., and the fingers 2^1^ mm. ; in a male 

 specimen of the length of 120 mm., on the contrary , these 



Notes from the Leyden IMuseum. 



