REPORT ON THE GASTEROPODA. 555 



point of the pillar, where there is a small canal, which is sometimes narrow, well-marked, 

 and slightly oblique. Outer lip perfectly level in its front surface, nearly semicircular in 

 its curve, slightly patulous on the base, and joining the point of the pillar at nearly a 

 right angle. Inner lip very short, but continuous across the body, thin and slightly 

 twisted down the pillar, the tip of which is truncated to form the generic canal, which is 

 more or less minute, narrow, and oblique ; behind the lip is a shallow umbilical depression. 

 H. 0-057 in. B. 0-027. Mouth, height 0'02, breadth 0-014. 



The paler specimens from Flinders Passage, which I take to be this species, are larger. H. 0091. 

 B. - 043. Mouth, height 0-03, breadth 0-022 ; the proportions, however, are identical. 



This species, though smaller, has a very strong general resemblance to Bittium pusilluvi 1 (Turri- 

 tella or Mesalia), Jeffr., from the Mediterranean, but has the spiral threads fewer ; the form and 

 arrangement of these, especially on the base, is different, and the tip of the apes is smaller. 



19. Bittium diplax; n. sp. (PI. XXXVIII. fig. 4). 

 October 6, 1874. Amboyna. 15 to 20 fathoms. 



Shell. — Very small, high and conical, pointed, pale sandy-coloured, reticulated, 

 bicarinated, with a small rounded tip, short convex whorls, an impressed suture, a small 

 short flatly conical base, and a small round mouth. Sculpture : Longitudinals — there are 

 from 10 to 15 small narrow slightly arched riblets, which above at the suture and on the 

 base are barely visible, but rise into little sharpish tubercles on crossing the spiral 

 threads ; they are distinctly to be seen on the first regular whorl, and are more numerous 

 there than toward the last whorl ; in the full-grown shell one or two of these riblets swell 

 into varices, which appear on the base. Spirals — there are on each whorl two fine 

 rounded threadlets, dotted with fine rounded but sharpish tubercles, where the longi- 

 tudinal riblets intersect ; they are parted by a shallow flat interval of nearly double their 

 width ; above these the conical sloping shoulder of each whorl has only the feeblest trace 

 of one or two spirals, of which one may be seen just below the suture ; below the 

 periphery are two rather sharper but untubercled spirals, of which the upper lies at the 

 insertion of the outer lip, and can be seen in the suture all up the spire ; these two 

 basal spirals are parted by a small shallow square-cut furrow ; within these spirals the 

 base is flatly conical, slightly marked with radiating lines of growth, and occasionally 

 with two very faint spiral threads close in to the pillar. Colour white, or sandy, with a 

 tinge of chestnut toward the tip. Spire high and narrow, with conical barely convex 

 profile lines. Apex consists of 2^ whorls, which are subdiscoidal to dome-shaped as the 

 first whorl and a half are flat and the extreme tip is not raised. Whorls 9 in all, short 



1 This is an unquestionable Bittium ; in full-grown specimens the base is " grooved " quite distinctly by the 

 generic canal. Dr Gwyn Jeffreys' specimens must have been immature, in which state the canal does not appear. 



2 &iwXa%, in double folds, such being the sculpture. 



