DUTCH BORNEO-EXPEDITION. 151 



covered with a brownish yellow epidermis and provided 

 with a black line below the suture and a narrow reddish 

 brown zone, upon the keel of the last whorl ; the sculpture 

 consists of rather faint lines of growth ; nuclear whorls 

 nearly smooth , with only faint plicae near the suture , 

 next whorls with spiral striae , the two last whorls moreover 

 with oblique grooves, which give to the surface the ap- 

 pearance of being covered with oblique rugosities, which 

 extend below the keel, but towards the umbilicus the spiral 

 striae prevail, the other sculpture becoming obsolete. 

 Spire conical, moderately elevated; whorls S'/gi rather flat, 

 with a superficial suture , last whorl large and with a rather 

 sharp keel; base of the shell more inflated, somewhat 

 compressed near the keel. Aperture large, not descending, 

 slightly oblique rhomboid, peristome straight, obtuse; 

 upper margin siuuous, lower margin regularly rounded, 

 passing without angle in the columellar margin, which is 

 only slightly reflected near the umbilicus. 



Diam. maj. 64, min. 53, alt. 33 mill.; apert. lat. 35, 

 alt. 27 mill. 



Localities: Nanga Raoen, May 1894 (Büttikofer). — Mount 

 Liang Koeboeng (Büttikofer). 



Of the specimen from Mt. Liang Koeboeng, with broken 

 shell , I have made the anatomical notes. 



This species , which I have named in honour of the 

 Zoologist of the expedition , is allied to H. densa , but the 

 shell is much larger than the largest specimen recorded 

 by V. Martens (Ostas. Landschn. p. 230) which is only 54 

 mill, in diameter; the aperture is proportionately larger, 

 the shell thinner, the umbilicus much smaller, and the last 

 whorl broader. The sculpture is rather similar in both species. 



Anatomy: The buccal mass is large , long 9 , high 

 10 mill., rounded triangular, the radula-sac very slightly 

 projecting; from the upper part proceeds a long oesopha- 

 gus, which shows two enlargements, the first immediately 

 behind the buccal mass and followed by a sudden constric- 

 tion ; from this latter the second reaches unto the place 



Notes from the Leyden. M^useum, "Vol. X"VII. 



Ï 



