Manwick.—7 he Struthiolariidae. 173 
The position is by no means so confused as the fossil-lists would show, 
but it is a difficult matter to supply an absolute proof, especially as the 
evidence is largely negative. It is impossible, for instance, to take all 
the records of S. papulosa, and to establish the correctness or incorrect- 
ness of each identification. But since, in the extensive collections examined 
sequence of species was rved, it is a fair inference that such strati- 
graphical limits prevail саак the country. 
Previous to the appearance of Suter's bulletins the identification of 
Tertiary Mollusca from Hutton's catalogue was pure guesswork, and th 
greatest credit must be given to Mr. Suter for the improvement he effected 
in the status of New Zealand Tertiary palaeontology. It must, however, 
be recognized that, owing to the great amount of ground co vered, many 
of his specific usages were applied too widely, while in some cases, through 
bad material, altogether wrong identifications were made. 
The ta table giving stratigraphical ranges of species of Struthiolaria on 
page 172 is therefore based on identifications made during the course of 
this revision only, and, except where correlations of South “Island Pliocene 
localities are concerned, is claimed to give fairly accurately the strati- 
graphical limits of the different species. 
For valuable help in the preparation of this paper by the loan of 
specimens, &c., my thanks are due to the following: Miss M. K. Mestayer, 
Dr. J. Henderson, Professor R. Speight, Messrs. H. J. Finlay, the late 
R. Murdoch, and W. R. B. Oliver; also to Mr. P. G. Morgan, Director of 
the Geological Survey, for his permission to publish 
PART IL—SPECIFIC CLASSIFICATION. 
1. Genus MOoNALARIA n. g. 
Genotype : Struthiolaria tuberculata subsp. concinna Suter, 1917. 
Shell somewhat small, ovate, umbilicus closed in the adult, conch- 
keeled and ШО; outer lip reflexed, thickened, concave above, 
broad 
then produced in a sweeping curve into a broad rounded wing opposite 
the lower keel, columella straight, aperture produced into a short widely- 
open canal. 
This genus differs from Struthiolaria in the contour of the outer lip, 
and the presence of a straight columella. 
Monalaria concinna (Suter), 1917. (Plate 11, figs. 1, 2, 3.) 
1917. Struthiolaria tuberculata Hutton VY concinna Suter, N.Z. Geol. Surv. 
Pal. Bull. No. 5, p. 9, pl. ii, fig. 9 
Shell rather small, ovate; spire broad, gradate, a little over half the 
height of aperture ; whorls 6, later ones strongly shouldered ; sculpture, 
t 2 conch-whorls convex, with 5 stro ng but narrow spiral ridges with 
sen im interspaces, on third whorl they are reticulated by curved axials 
slightly. stronger and wider apart than spirals, 3 posterior spirals much finer 
than other 5; fourth whorl strongly angled with wide shoulder, a fairly 
13 strong rounded axials which commence a short distance Ja suture 
and are arched, anterior end being slightly in advance, they are not so 
