36 GASTEROPODA. 



CHRYSOSTOMA. 



Globose, turbinated, polished, perforated. Umbilicus covered by a 

 strong callosity ; whorls few, rounded ; columella callous, regularly 

 arched. 



151. C. fullHiliata, sp. nov. "Whorls convex, smooth, umbilicus 

 generally open ; colour various, generally pink, with white radiating 

 markings round the sulcus, but sometimes white zig-zag markings 

 extend over the whole shell. Sometimes olivaceous, with or without 

 white markings. Length, '3 ; breadth, '3. 



Chatham Islands only. 



152. C. Simillata, */> nov. Whorls convex, faintly spirally 

 striated, umbilicus generally closed. Pink or pinkish brown, generally 

 with white markings on the spire. Length, "3 ; breadth, "25. Rather 

 more produced than the last. 



Chatham Islands only. 



153. C. inCOllSpiClia, sp. nov. Depressed, whorls convex, faintly 

 spirally striated ; umbilicus always open. Brownish green or brown, 

 more or less marked with purplish brown and white. Length, '15 ; 

 breadth, '2. 



154. C. rOSSa, sp. nov. Depressed, whorls convex, smooth, faintly 

 transversely striated ; pinkish white, with three or four narrow pink 

 spiral bauds, and some purplish spots on the body whorl near the 

 suture. Length, 15 ; breadth, 23. 



Stewart's Island. 



POLYDONTA. 



Conical ; base flat, with a deep axial cavity ; mouth sub-rhomboidal ; 

 columella twisted. 



155. P. tllbercniata, Gray, Diejf. N.Z., ii., p. 239. Spire 

 rather produced, whorls flat, with four spiral rows of rounded tubercles ; 

 base spirally striated ; columella with a strong fold posteriorly, anterior 

 portion nearly smooth ; axial cavity with three spiral ridges. White 

 or purplish white, tubercles pinkish or brownish purple; base white. 

 Length, '85 ; breadth, I'l ; angle of spire, 62. 



In the young the body whorl is much angled and surrounded by a 

 marginal row of larger tubercles ; the colours also are brighter. 

 Common. Chatham Islands. 



156. P. ehathamensis, sp nov. Whorls flat, with an elevated 

 upper edge, and, together with the base, spirally striated ; columella 

 with a slight posterior fold, anterior portion nearly smooth ; axial 

 cavity small, smooth. White with pink or brownish purple markings ; 

 base white with interrupted pink spiral lines. Length, '3 ; breadth, 

 '35 ; angle of spire, 70. 



Chatham Islands only. 



157. P. tiarata, Quay ; P. elegant, Gray, Deiff. N.Z , ii., p. 238. 

 Whorls slightly convex, often with an elevated upper edge, and six or 

 seven spiral rows of beads ; columella with a slight posterior fold, 



