DUTCH BORNEO-EXPEDITION. 139 



As we know, the geographical distribution of some spe- 

 cies of this genus , namely of those that inhabit also the 

 sea, is rather large. It appears to me, however, probable 

 that other species which occur exclusively in fresh water, 

 are distributed over a small area , inhabiting e. g. one 

 single large river with its tributaries. To the latter seems 

 to belong Pal. sintangensis , the specimens of which have 

 been collected by the Expedition in the interior of Borneo 

 at Sintang. 



Pal. sintangensis is apparently a species of small size, 

 the largest specimen, a male, being only 57 mm. long 

 from the apex of the rostrum to the tip of the telson. It 

 bears a considerable resemblance to Pal. (Eupal.) Ritsemae 

 de M. from Atjeh , exhibiting indeed almost the same cha- 

 racters, but it differs at first sight by the size of the 

 eggs. An ova-bearing female and a younger one of Pal. 

 Ritsemae, original type-specimens from the collection made 

 by capt. Storm, are lying before me: the eggs are very 

 numerous and small, being only 0,6 mm. long 

 and 0,5 mm. broad. 



The two females of Pal. sintangensis , however , carry a 

 much smaller number of eggs and these eggs 

 are more than twice as long and more than 

 twice as broad as those of the Atjeh species: 

 they are 1,6 mm. long and 1,2 mm. broad. 



The ensiform rostrum has nearly the same form as that 

 of Pal. Ritsemae and reaches to the end of the antennal 

 scales, in young individuals it extends sometimes even 

 slightly beyond them. The upper margin is usually slightly 

 convex above the eyes and the apex mostly a little turned 

 upwards ; in a very young male specimen even almost 

 the whole rostrum is slightly upturned and tapers more 

 than usually towards the apex (Fig. Id). On the upper 

 margin 12 or 13 teeth are observed, rarely 9 or 10; the 

 first tooth is commonly separated from the second by an 

 interval twice as large as between the following, which 

 above the eyes are equidistant and mostly placed close 



Notes from th.e Leyclen IMuseum, Vol. XX- 



