PLEUEOTOMA. 



47 



By the short canal and longitudinal costae this shell presents 

 some analogy with Drillia, but it differs in the position of the 

 sinus, which is distant from the suture, and in the absence of 

 a posterior callosity on the columellar border. The length of the 

 anterior canal is not of much value in systematics, and in some 

 species of Fleurotoma may only indicate sexual differences. The 

 ribs and position of the sinus are characteristics recalling Surcula. 



Dimensions. — Length 14 mm. ; breadth 5 mm. ; length of 

 aperture 6 mm. 



Form, and Loc. — Pliocene : New Zealand. 



G. 1618. Two adult examples, from Wanganui. 



G. 9497. An exceptional form, from Shakespeare Cliff. 



Siir James Sector Coll. 



Pleurotoma buchanani, Hutton. 



1873. Pleurotoma buchanani, Hutton, Cat. Tert. Moll. N.Z. p. 4. 

 1893. Pleurotoma buchanani, Hutton, Linn. Soc. N.S.W., Macleay Mem. 

 Vol. p. 50, pi. vi. fig. 26. 



" Shell elongate -fusiform. Whorls obliquely longitudinally 

 plaited, and with fine spiral ribs below the sinus area ; above the 

 sinus area smooth, concave, with a slight ridge at the suture. 

 Between 11 and 15 longitudinal plications on a whorl. Aperture 

 oval, canal produced, rather bent." — Hutton. 



Protoconch composed of two oblique smooth turns, the anterior 

 portion having four deep spiral sulci, cutting through the small 

 longitudinal costte of the brephic stage, into which the protoconch 

 imperceptibly passes. 



This species might be classified with Sxtrcula ; the sinus is 

 situated half-way between the suture and the periphery, and is 

 not deep ; the development of longitudinal costae removes it from 

 Pleurotoma, sensu stricto. 



Dimensions. — Length 20 mm. ; breadth 7'5 mm. ; length of 

 aperture 10" 5 mm. 



Form, and Loc. — Pliocene : New Zealand. 



G. 1617. Adult and juvenile specimens, from Wanganui. 



G. 9496. Three specimens, from Shakespeare Cliff. 



Sir James Hector Coll. 



