48 Macieay Memorian Vouume. 
Genus PLEUROTOMA. 
Key to species. 
A. No callus in aperture. 
1. Whorls not spirally ornamented. 
Whorls sharply keeled... sae .. P. pagoda. 
2. Whorls spirally ribbed. 
a. No longitudinal ribs or nodules. 
a. Whorls keeled. 
Spirals below the keel 15... sta) UPraloude: 
Ms e ae CONT ... LP. nexilis. 
g. Whorls not keeled. 
Spirals below the sinus 11-12 ... LP. cheesemant. 
b. Longitudinally ribbed. 
a. Suture not margined. Longitudinal 
ribs 15 to 20)... Sr bf .. LP. protensa. 
g. Suture slightly margined. 
Longitudinal ribs 11 to 15 we =P. buchanant. 
s. 5; LG tony . LP. plicatella. 
y. Suture strongly margined. 
Longitudinal ribs 13 to 16 .. P. wanganutensis. 
ce. Shoulder with a row of nodules. 
Spirals below the shoulder 7 . 2. tuberculata. 
B. A posterior callus in the aperture (Dri/ia). 
Spiral striation distinct —... . P. equistriata. 
a Pe faint Ao ..- LP. alabaster. 
a e absent ae soo 4 UES 
Prevrotoma pacopa, Hutton, Cat. Tertiary Moll. of N.Z. p. 5. 
(Plate vi. fig. 21.) 
Shell elongato-fusiform. Whorls smooth, strongly keeled. Below the keel 
a concavity bordered by a low spiral rib. Aperture ovate, contracted anteriorly ; 
canal long, straight, narrow. Length 18mm.; breadth 6mm. 
Locality.—Petane, Matapiro. 
