TROCHUS. 43 



delicatulus PHILIPPI, Zeitschr.f. Mai. 1846, p. 105. Conchy I. Cab., 

 p. 176, t. 28, f. 1. (pi. 12, figs. 70, 71.~)Polyodonta elegans GRAY, 

 in Yate's Account of New Zealand, p. 309. 1835. 



This small trochid is evidently allied to the preceding species in 

 the peculiarly straight columella and the somewhat tumid aspect of 

 the upper part of each whorl. From T. erythrreus and its allies the 

 flat base, and especially the insertion of the columella on the side, 

 instead of in the center of the false-umbilicus will at once separate 

 this form. Dentition (pi. 50, fig. 4.) 



T. CHATHAMENSIS Hlltton. 



Whorls flat with an elevated upper ed^e, 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. Alt. 7J, diam. 9 mill. (Hutton.) 



Chatham Is. 



Polydonta chathamensis HUTTON, Cat. Mar. Moll. N. Z., 1873, p. 

 36. 



Section ANTHORA Gray, 1857. 



Anthora GRAY, Guide Syst. dist. moll. Brit, mus., p. 148. 

 T. VIRIDIS Gmelin. PL 3, figs. 16, 17 ; Vol. x, pi. 40, fig. 21. 



Shell conical, solid, false-umbilicate ; spire conic, w r ith nearly 

 straight outlines, apex acute ; whorls about 7, nearly planulate, or 

 sometimes a little bulging at the upper and lower margins, the last 

 whorl carinate at periphery ; color dull gray, whitish or greenish ; 

 sculpture of upper surface consisting of five series to each whorl of 

 rounded, bead-like granules, between which are visible numerous 

 very minute spiral striae, in the interstices of which oblique in- 

 cremental stria? are prominently shown (under a lens) ; base plano- 

 concave, concentrically striate, the striae unequal, disappearing 

 toward the outer edge ; aperture suboval, brilliantly nacreous 

 and iridescent within, outer lip lirate within, basal margin thick- 

 ened, subdentate, uniting with the columella in a regular curve; 

 columella oblique, with a deep fold near its insertion, smooth within ; 

 umbilical area with 3 or 4 spiral ribs ; parietal wall smooth, covered 

 with a brown callus. Alt. 20, diam. 19 mill. 



New Zealand ; Chatham Is. ; Norfolk Id. 



T. viridis GMEL., Syst. Nat. xiii, 1788, sp. 34, p. 3572. REEVE, 

 Conch. Icon, f. 79. (Vol. x, pi. 40, fig. 21). Polydonta tuberculata 



