DUTCH BORNEO-EXPEDITION. Ill 



rate the cardiac region from the intestinal one and shal- 

 low depressions are observed between the somewhat convex, 

 anterior branchial lobe and the much smaller posterior. 

 The slightly concave posterior margin of the cephalothorax 

 is just half as broad as the latter. 



The post-frontal ridge is only represented by the promi- 

 nent epigastric lobes, that are wrinkled, advanced, con- 

 fluent with the protogastric regions , but subsiding 

 abruptly towards the front; the mesogastric furrow 

 is deep and extends almost to the middle of the gastric 

 region, but the mesogastric area is , however, confluent 

 backwards with the protogastric lobes. The postorbital 

 groove is shallow. The front fully agrees with that oï Pot. 

 hendersonianum^ but it is slightly narrower and the 

 lateral margins are somewhat less oblique. The upper sur- 

 face of the front is a little more concave in the middle 

 and the postorbital groove is smooth. 



The nearly transverse upper margin of the orbits (Fig. 

 12«) is slightly sinuous and the acute external orbital 

 angles reach not as far forward as the front. At a short 

 distance behind the outer angle of the orbits one observes 

 a rudimentary epibranchial tooth, represented 

 only by a slight notch in the margin and the 

 small prominence passes backward and inward, for a very 

 short distance, as an obscure crest, that is just as long 

 as the distance between the extra-orbital angle and the 

 epibranchial tooth. A little more backward, the cephalo- 

 thorax appears very slightly swollen outside of and beneath 

 the antero-lateral margin and, posterior to the antero-lateral 

 crest, the whole margin of the cephalothorax is marked 

 with oblique raised lines. To the naked eye the upper 

 surface of the cephalothorax appears smooth and shining, 

 but, examined under an ordinary lens , a fine and close 

 punctation is observed on the whole surface; the puncta 

 are of different size, larger puncta being distributed amongst 

 numerous microscopical other ones. Strangely enough the 

 right half of the cardiac region is quite smooth, devoid of 

 Notes from the Leyden IMuseum, "Vol. X^X.1. 



