THE MOLLUSCA—HEDLEY. 437 
more rapidly increasing whorls, different plan of sculpture, and 
especially by a habit of plugging and breaking off the upper 
whorls from time to time. Animal unknown. 
Type.—C. decollatus, Hedley. 
The genus is founded on a species from Funafuti. I have also 
a cogeneric but apparently distinct species from Oubatche, New 
Caledonia, which is 15 mm. long; white, with a few scattered 
brown dots ; without the longitudinal plications of the Funafuti 
species, but rather more distinctly cancellated by longitudinal 
sculpture. Iam also disposed to include under Contwmaa the 
species which Melvill and Standen describe* as Mathilda eurytima, 
whose “canali producto” so ill agrees with Mathilda, Perhaps 
this M. ewrytima may be the young of the Oubatche shell just 
mentioned. The genus is also represented from Torres Straits. 
CoNTUMAX DECOLLATUS, Sp. Nov. 
(Fig. 25). 
Shell narrow, conical, above rounded, 
below turreted, solid, invariably decollated. 
Colour, dull white. Whorls of an uncer- 
tain number, the specimen figured has 
seven, and I estimate that five more have 
been lost. Sculpture—the shell has three 
stages, which merge into each other, but 
which apart might seem to belong to 
different species. None of a fairly large 
series before me show the apical whorls, 
the summit being in every instance and in 
successive stages broken off. The youngest 
whorl before me is rounded and crossed by 
several fine raised spiral lines. Later the 
median line enlarges and originates an 
angle, and a faint longitudinal sculpture 
appears. Further on, the whorl is sharply 
angled by a strong keel, below which are 
two minor keels, and on the shelf above 
are five delicate spiral lines, all of which 
are more or less beaded by transverse 
sculpture. On the antepenultimate whorl Fig. 25. 
commence longitudinal plications which 
rapidly develop to their maximum on the last whorl. Here they 
are six in number, oblique, commencing at the suture, most 
prominent on the shoulder and vanishing at the basal keel. 
The base is hollow, overhung by a thick basal ridge, within 
which is a second lesser one, the remainder of the base being 
faintly concentrically striated. Aperture scarcely oblique, squarish, 
* Melvill & Standen—Journ. Conch. viii., 1896, p. 310, pl. xi, fig. 73. 
