SuteR.—On New Zealand Mollusca. 131 
it could not be %. niteda, but the specimens correspond with 
Pfeiffer’s diagnosis of H. novare, with the only difference that 
some of Musson’s specimens have 4-1 volutions more, and are 
therefore larger than the examples collected by Hochstetter. . 
On examining the animal and dentition I saw that it is not a 
Flammulina, as first supposed, but an Ariophanta, the only 
species of this genus known to me to occur in New Zealand. 
It may therefore be of interest to have the dentition described 
and figured. 
Jaw (fig. 26) membranaceous, smooth, upper margin 
arched, lower margin almost straight, with an indistinct 
median projection, ends tapering, faintly longitudinally and 
vertically striated. 
Radula (fig. 27) tongue-shaped, formula 42—1—42, of 
which 10 to 12 are laterals ; transverse rows of teeth straight. 
Central tooth long and narrow, with one long reflection, and 
a short, stout cutting-point, extending a little over the next 
row of teeth. Laterals broader, unicuspid, with a broad, blunt 
cutting-point of the same length as the central. A large 
number of intermediate teeth follow; they are oblique, with a 
bicuspid reflection, and one stout, oval cutting-point. Mar- 
ginals sinuate, bicuspid. 
20. Otoconcha dimidiata, Pfeiffer, sp. 1854. Plate XVIII., 
fig. 28, and Plate XIX., fig. 29. 
Some time ago I found a single specimen of this curious 
mollusc at Port Hills, Lyttelton, the radula of which differs 
slightly from that described and figured by Professor Hutton 
(Trans. N.Z. Inst., vol. xvi., pl. ix., fig. Y). The specimen was 
rather a young one. | | 
Jaw (fig. 28). It has hitherto been said that the jaw of 
Otoconcha is ribbed, and at first sight it would seem to be so. 
I have, however, quite a different opinion. The outlines of 
the jaw figured are decidedly those of an oxygnath jaw, which 
supposition is supported by the distinct longitudinal striation, 
which is very often seen in the jaw of the Limacide. The 
most irregular denticulation of the cutting-margin points to 
the fact that this jaw cannot be considered as ribbed, but as 
channelled by the action of the exceedingly strong cutting- 
points of the radula. 
I therefore describe the jaw of Otoconcha as oxygnath, 
smooth, longitudinally striated, with a strong median pro- 
jection inferiorly, irregularly channelled, the channels in- 
creasing in depth towards the cutting-margin, which is deeply 
and irregularly denticulated. Ends blunt. ” 
The jaws of old animals represent only a narrow ledge 
with blunt denticulations on the inferior edge; perfectly worn 
out by the action of the teeth. 
