DUTCH BORNKO-EXPEOITION. 87 



mewhat less enlarged than the cephalothorax oï Pot. 

 borneense and of the variety hilaris. Tlie upper surface is 

 a little less convex in the antero-posterior direction than 

 in Pot. borneense var. hilaris and the posterior half viz. 

 the cardiac and intestinal regions together with the con- 

 terminous parts of the undivided branchial region, appears 

 rather flattened from side to side. The cervical groove is 

 interrupted and the oblique anterior furrows have the 

 same direction as in Pot„ borneense var. hilaris^ for 

 they would make a right angle with one another, 

 when prolonged backwards. The postfrontal ridge is as 

 little developed as in Pot. borneense ; the slightly 

 advanced epigastric lobes, that are foveate anteriorly, smooth 

 above and not limited off posteriorly from the gastric 

 region, are well-defined, but on each side of them one 

 observes, as in the two preceding species, only the rugose 

 and coarsely punctate slope by which the gastric region 

 subsides towards the post-orbital furrow. The mesogastric 

 furrow is short and narrow, the anterior end of the meso- 

 gastric region is therefore not defined. The upper surface 

 is finely punctate, rather closely on the branchial, cardiac 

 and intestinal regions, but on the gastric region the puncta 

 are less numerous ; they are visible to the naked eye, the 

 carapace, however, appears smooth and shining. The shallow 

 depressions that bound the cardiac region are often in- 

 distinct. 



The front resembles that of Pot. borneense var. hilaris. 

 The free border measures one fourth the width of the 

 carapace and is straight, not bayed at all; the lateral 

 margins of the front have the same oblique direction and 

 form obtuse angles with the anterior margin. Prof. Hil- 

 gendorf informs me that in the type of Pot. borneense 

 these angles are more rounded off, so that the anterior 

 frontal margin appears narrower, von Martens indeed 

 says that it measures one third the width of the cephalo- 

 thorax. As in the other form the mesogastric furrow is 

 not continued on the front. The front is flattened, not 



Notes f'roixi the Leytleii Museuin, Vol. JCXJ, 



