248 CEEPIDDLA. 



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

 G. 9705. Several examples illustrating stages of growth and 

 variation in the development of the surface ridges. 



W. B. D. Mantell Coll. 



Crepidula incurva, Zittel. 



1865. Crepidula incurva, Zittel, Reise der Novara, Palaontologie, Bd. i. 



Abth. ii. p. 44, taf. xv. figs. ^a-h. 

 1873. Crijpta incurva, Hutton, Cat. Tert. Moll. N.Z. p. 14. 



Shell elongate, extremely convex,, flattened on one side ; apex 

 incurved, not situated on the margin, thickened; "internal septum 

 concave, or almost flat, extending to the middle of the shell." — 

 Mutton. The growth-lines produce corrugations on the surface. 



Dimensions. — Height 26 mm.; breadth 24 mm. 



Form, and Loc. — Miocene (?) : Motanau, Marlborough, New 

 Zealand. 



G. 9566. A large specimen affixed to a piece of argillaceous 

 limestone, the upper surface of the shell only being visible ; the 

 surface is very irregular, owing to the development of corrugations 

 of growth. &ir James Hector Coll. 



Subgenus lANACTJS, Morch. 



[Cat. Yoldi, 1852, p. 146.] 



Shell depressed, frequently concave above, apex posterior, 

 slightly lateral. 



Type. — Crepidula plana, Say. 



Crepidula (lanacus) unguiformis, Lamarck. 



1822. Crepidula unguiformis, Lamarck, Hist. Nat. Anim. sans Vert. t. vii. 



p. 642. 

 1873. Crypta [Janacus) unguiformis, Hutton, Cat. Marine Moll. N.Z. p. 32. 

 1880. Crypta unguiformis, Hutton, Man. N.Z. Moll. p. 87. 

 1886. Crepidula {Janacus) unguiformis, Tryon, Manual of Conchology, 



vol. viii. p. 130, pi. xxxix. figs. 66-8. 

 1893. Crepidula unguiformis, Hutton, Linn. Soc. N.S.W., Macleay Mem. 



Vol. p. 62. 

 1893. Crepidula unguiformis, Tate, Trans. Eoy. Soc. South Aust. toI. xvii. 



pt. 2, p. 330. 



