TRuEMAN.—4A New Fossil Gasteropod from New Zealand. 601 
A New Fossil Gasteropod from New Zealand. 
By А. E. Trueman, D.Sc., F.G.S., University College of Swansea. 
Communicated by J. Marwick. 
[Read before oe Дин» Philosophical Scciety, 10th October, 1923 ; received by Editor, 
November, 1923 ; issued separately, 28th August, 1924.] 
LI 
THROUGH the kindness of Mr. John Marwick the writer has been able to 
study a small series of fossil gasteropods collected recently by Mr. M. Ongley, 
of the New Zealand Geological Survey. The fossils were collected from 
some limestones in the Mangarua Creek, in the Tapuwaeroa Valley of the 
East Cape District, North Island. Mr. Marwick informs me that “no 
work has been done on the fauna of the beds from which the specimens 
come, so the age cannot be stated. It has generally been considered as 
Cretaceous (probably Lower), because of the frequent occurrence of large 
Inoceramus ; — of the Mollusca seem to have Jurassic affinities, so the 
horizon is an o z 
The material Submitted to the writer pen about ae more or less 
fragmentary gasteropods, most of which were embedded in a peculiarly 
hard pale-blue limestone. ые, the шо were bind of several 
lamellibranchs, including Inoceramus. 
he writer believes that the gasteropods are distinct from any apes 
that have hitherto been described; they are here called Katosira 
striata n. sp. No one specimen exhibits all the characters, but as the 
specimens vary considerably aren themselves it will be adv antageous 
first to describe the holotype in det 
Katosira obliquestriata n. sp. 
Dimensions of holotype: Length of shell (estimated), 35 mm. ; width 
of shell, 33 per cent.; length of spire, ? 70 per cent.; spiral Mio. 106° ; 
apical angle, 24°. 
The holotype (fig. a) is a fairly complete specimen, but the uppermost 
whorls are missing, as in all other large specimens that have been extracted 
from the matrix. Whorls are rather flat, the widest part being near anterior 
end; sutures are shallow, and there is a tendency for last whorl to be 
moulded on preceding whorl. 
Shell practically smooth; ornament consists De very fine axial striae 
and a few faint spirals. Axial striae regularly spaced, “and after curving 
slightly iu elt from posterior border they a e rie sharply to left and 
with a marked imus ty. Spirals are few in number, and 
exceedingly fain t except near sutures 
Six whorls present in holotype. These show a slight change in whorl- 
pe odia, earlier whorls being somewhat flatter than 
later. Boop for the ina iggy y of spirals near sutures in later — 
there is no change in character of ornamentation in whorls that are pre- 
served. Ашын part p last whorl (the underside or base of shell) bears 
axial striations crossed by extremely faint spirals. 
The shell is unusually thick. 
Holotype: The holotype is in the N.Z. Geological Survey collection. 
M topotype has also been presented to the British Museum of Natural 
istory. 
