568 THE VOYAGE OF H.M.S. CHALLENGER. 



of any kind. Colour whitish horny. Spire conical, slightly scalar. Apex small, but 

 bluntly rounded, and neither sharp nor sculptured. Whorls 3^, of regular but rather 

 rapid increase, a little tumid, and convex but flattened, in a line parallel to the axis ; the 

 base is tumid and somewhat produced. Suture strong, impressed, and almost a little 

 canaliculate. Mouth perpendicular, oval, not at all pointed. Outer lip thin, a little 

 incurved above, slightly patulous in front, and projecting beyond the pillar, between which 

 projection and the pillar it retreats as a slight and open sinus. Pillar perpendicular, a 

 little hollowed, twisted, and truncate. Inner lip spread out over the body-whorl and 

 behind the pillar, so as to conceal and almost close the umbilicus, below which it crosses 

 with an oblique thin edge to join the front of the pillar below its twisted truncation. 

 Umbilicus not small in itself, but almost quite hidden. H. 0"089 in. B. 0*06, least 0*047. 

 Penultimate whorl, height 0*02. Mouth, height 0'052, breadth 0-039. 



This is one of those unsatisfactory cases where a species is classed under a particular genus for 

 want of a better. The texture of the shell is somewhat like that of Litiopa, but it utterly wants 

 the pointed and sculptured apex, the truncation of the lip is blunt, and the species much more 

 resembles a Limnwa than anything else. 



There are no varices nor any thickening of the outer Hp to connect it with Alaba (see Adams' 

 Genera, vol. i. p. 241, and Ann. and Mag., 1862, vol. x. p. 294; and E. A. Smith, Proc. Zool. Soc. 

 Lond., 1875, p. 537), and the truncated column distinguishes it from Diala. But, of course, if 

 Alaba {Diala) pida, Ad., with a faint approach to a truncation, may be admitted to the subgenus, 

 whose characteristic features already at each important point contradict those of the genus itself, it 

 is hard to say what may or may not be united to so elastic a group, and I really know of nowhere 

 else to put it. 



3. Alaba (Diala) albugo, n. sp. (PI. XLII. fig. 3). 



Station 186. September 8, 1874. Lat. 10° 30' S., long. 142° 18' E. Off Wednesday 

 Island, Cape York, North-east Australia. 8 fathoms. Coral mud. 



SJiell. — Strong, elongate, conical, blunt-tipped, fulvous, white-spotted, 1 very faintly 

 subscalar, spirally striated, with a largish body -whorl, oval mouth, and sharply impressed 

 suture. Sculpture : Longitudinals — there are very faint rather straight lines of growth. 

 Spirals — there are on the last whorl above the periphery about seven small broadish flat 

 unequal bands, which are parted by very small shallow white rugged furrows ; the band at 

 the edge of the base where the periphery occurs is slightly stronger and is more round 

 than the rest, and forms a slight keel ; very similar sculpture is reproduced on the base, 

 but a little flat space encircles the pillar. Colour bright yellow-brown, scored with white 

 spiral lines and dotted with round white spots, arranged in blurred groups, forming broad 



1 Hence the name. 



