Murpocu.—Some Tertiary Mollusca. 157 
Some Tertiary Mollusca, with Descriptions of New Species. 
Ву К. Мовросн. 
[Read before the Wanganui Philosophical Society, 11th December, 1922; received by 
Editor, 31st December, 1922 ; issued separately, 26th May, 1924.] 
Plates 8-10. 
PINNA. 
In his Catalogue of the Tertiary Mollusca and Echinodermata of New Zealand, 
1873, page 26, Hutton described three species of Pinna—viz., lata, plicata 
served, and the sculpture is therefore the radiating furrows on the interior 
surface of the valves. For the loan of the drawings prepared by the late 
- Buchanan I am indebted to Mr. P. С. Morgan, Director of the 
Geological Survey. I am also indebted to Mr. H. J. Finlay, of Dunedin, 
for the loan of specimens. 
Pinna lata Hutton. (Plate 8, figs. 1, 2, and Plate 9, fig. 2.) 
Original Description.—Broadly triangular, with concentric striae, anterior 
end rather excavated. Height, 8; length, 7-25; angle of apex, 60? 
Locality, Cobden. 
In view of the specimens before me, there appears to be no doubt that 
the above description refers to a large fragment of the wide posterior end. 
A close serutiny of Buchanan's figure shows a very imperfect shell with 
some radiate riblets on the narrow end, of which Hutton makes no mention. 
A specimen received from Finlay, doubtfully from Caversham sandstone, 
Shell large, narrowly triangular, angle of apex 33°, beak pointed, dorsal 
margin straight, posterior end oblique produced below, basal margin a little 
convex posteriorly. Clothed with a thick dark periostracum, nacreous 
beneath.- Sculpture: Apical half and from median area dorsally with fine 
radiating riblets, crossed by smaller threadlets, both narrower than inter- 
spaces, on basal area irregular growth-lines and undulations rather strongly 
curved to median area, where they are wave-like and ually widening 
posteriorly, posterio-dorsal area with irregular growth-lines. The fine 
