114 SCAPHELLA. 



or three of which are plicatecl, the plications dying out as the adult 

 stage is attained. Pari passu with this phenomenon we find 

 in some individuals the incoming of tubercles at the periphery 

 of the whorls ; these are distantly situated, small at first and then, 

 becoming very large, the maximum size being reached with full 

 growth of the shell. On the other hand, we find individuals 

 in which these tubercles are not developed ; after the plications 

 on the earlier whorls had died out the remainder of the whorls 

 became perfectly smooth, as may be seen in examples of the species 

 in the living state. Clothed with prominent, spinose tubercles, 

 this species bears but little resemblance to typical forms of the 

 genus Scaphella; but when smooth it is readily comparable with 

 S. junonia. The last-mentioned characteristic, taken together with 

 its distinctly scaphelloid protoconch, enables the writer to assign 

 it to Scaphella, and it may be placed in the neighbourhood of 

 JEopsephia. The outer margin of the aperture is thin and reflected 

 outwardly ; columella covered over by a thin deposit of callus, 

 plications to the number of four. 



Dimensions. — Length 132 mm.; breadth 54 mm.; length of 

 aperture 88 mm. 



Form, and Loc. — Pliocene : Wanganui, New Zealand. 



G. 9504. Two specimens, with well-developed spines at the 

 periphery of the whorls. Sir James Hector Coll. 



Scaphella gracilis, Swainson (sp.). 



1821. Valuta gracilis, Swainson, Exotic Conch, p. 20, pi. xlii. 



1824. Valuta gracilus, Swainson, Quart. Journ. Sci. vol. xvii. p. 32. 



1832. Valuta fusus, Quoy and Gaimard, Voy. de I'Astrolabe, Zool. t. ii. 



p. 627, pi. xliv. figs. 7, 8. 

 1849. Valuta gracilis, Eeeve, Conch. Icon. pi. xvii. fig. 40. 

 1864. Valuta (Seapha) gracilis, Angas, Proc. Zool. Soc. p. 52. 

 1871. Valuta {Alcithae) gracilis, Crosse, Journ. de Conchyl. 3' ser. t. xi. 



p. 295. 

 1873. Valuta [Alcithae) pacijica var. gracilis, Hutton, Cat. Marine Moll. 



N.Z. p. 18. 

 1873. Valuta gracilis. Von Martens, List Moll. N.Z. p. 22. 

 1877. Valuta {Alcithae) gracilis, Kobelt, Jahrb. deutsch. malak. GeseUsch. 



p. 309. 

 1880. Valuta gracilis, Hutton, Man. N.Z. Moll. p. 62. 

 1882. Valuta [Alcithae) pacijica var. gracilis, Tryon, Manual of Conchology, 



vol. iv. p. 94. 



