MOLLUSCA OF THE ' CHALLENGER ' EXPEDITION. 273 



Nassaeia, Link. 



Nassabia amboynensis, n. sp. 



Oct. 6, 1874. Amboyna. 15-25 fins. 



Shell. — Ovate, conical, pointed, variced, brown-banded, a 

 very contracted base, with a short, recurved, and somewhat 

 twisted snout. Sculpture. Longitudinals — there are on each 

 whorl 11 or 12 (on the earliest about 10), strong, promi- 

 nent, well-defined, rounded, curved, and sinistrally inclined 

 ribs, of which about 2 on each whorl are stronger than the 

 rest ; these ribs extend to the base of the snout, and swell 

 up over, but are interrupted by, the suture which at top of 

 whorls cuts them off; they run with a sinistral twist down 

 the spire ; the rather deep interstices are fully broader than 

 the ribs : besides these, the whole surface is roughened with 

 slight unequal lines of growth, which are most distinct on the 

 earlier whorls. Spirals — the surface is beset with unequal 

 threads, of which about 6 on the body and 4 on the base are 

 stronger and more prominent than the rest ; the two in the 

 middle of the whorls are most so of all ; between these are 3, 

 4, or 5 unequal, raised, and sharpish round threads, especially 

 prominent on the longitudinal ribs the hollo w t s between these 



; are variable in width, deep, and flat-bottomed, though sometimes 

 filled by another minute thread; these intervals are finely scored, 

 while the threads are coarsely roughened and crumpled by the 



i longitudinal lines of grow 7 th : besides these, the surface is finely 

 fretted with microscopic spirals ; on the snout are about 10 

 coarsish somewhat crumpled threads, with minute sharp lines in 

 their interstices. Colour tawny white, with a broadish, infraperi- 

 pherial chestnut band and less continuous stains of the same up 

 to the suture and on the base and snout. Spire high turreted, 

 conical, small and sharp at the point, with an almost continuous 

 outline in spite of the deep suture. Apex partly broken, but 

 evidently consisting of 2 or 3 polished, rounded, turbinated whorls^ 

 Whorls 9, exclusive of the embryonic whorl, ventricose, rounded, 

 of regular increase ; but the last is somew T hat disproportionately 

 large ; the base is rounded, but contracted and a little flattened 

 toward the snout, which is ample, but not large, both as to length 

 and breadth, and advances straight in the axis of the shell, but 

 with a dextral twist and a strong backward bend on itself. Suture 



LINK. JOtJRN. — ZOOLOGY, VOL. XV. 21 



