112 GASTROPODA. [Aspidobranchia. 



KEY TO SPECIES. 



A. Shell elevated conical, cohimella with a strong biplicate tooth 



at base . . . . . . . . . . . . ringens. 



B. Shell depressed conoidal, cohimella with a small simple tooth 



at base . . . . . . . . . . . . takapunaensis. 



t 

 6. Trochus ringens, Menke, 1843. Plate 38, fig. 3. 



Monodonta ringens, Mke., Moll. Nov. Holl. Spec., 14 ; not of Philippi, 1846. 

 Trochus ringens, Mke. : Fischer, Coq. Viv., 213, pi. 71, f. 1 ; Man. 

 Conch. (1), xi, 81, pi. 11, f. 49, 50 ; Suter, P. Mai. S., ii, 262. 



Shell false-umbilicate, conical, spirally cingulate. Sculpture : 

 Spirally cingulate above, with 4 elegantly granulate ridges, the upper 

 and lower larger ; base with 8-9 granose cinguli. Colour yellowish, 

 maculate with chestnut and white. Spire conical, sides convex, 

 sharply pointed. Protoconch sharply pointed, spirally lirate, of about 

 2 whorls, white with pink spots. Whorls 7, planulate, the last 

 acutely carinated ; base slightly convex. Suture canaliculate. Aper- 

 ture rhomboidal, oblique, narrow. Basal margin sulcate-denticulate. 

 Columella strong, callous, oblique, strongly plaited, terminating below 

 in a large biplicate tooth. 



Diameter, 11 mm. ; height, 10 mm. Sometimes the height exceeds 

 the diameter. 



Type (?). 



Hob. Cape Maria van Diemen (C. H. Robson) ; Mokohinau 

 Island. 



Remarks. My specimen from Mokohinau has a slightly more acute 

 spire ; the colour is light brown, with chestnut-brown spots ; the 

 outer lip is distinctly lirate within ; the margins of the aperture are 

 united across the body- whorl by a rather thick callus, bearing a few 

 lirse. Diameter, 10-5 mm. ; height, 12 mm. Angle of spire, 62. 



7. Trochus takapunaensis, Webster, 1906. Plate 33, fig. 4. 



Trochus (Clancuhts) takapunaensis, Webst., T.N.Z.I., xxxviii, 1905 (190t>), 

 309, pi. 39, f. 2, 2a. 



Shell small, depressed conoidal, spirally cingulate. Sculpture : 

 Smooth rounded spirals, of which the 2 upper are closer together 

 and the others far enough apart to admit a fine spiral thread in the 

 radially striated hollow between them ; above the peripheral spiral 

 on the body-whorl is a narrower one, which appeared in the suture 

 of the third whorl ; base with 7 to 8 spirals, separated by furrows of 

 the same width. Colour yellow-grey, with very dark irregular patches, 

 all of which shade into white from left to right. Spire depressed 

 conoidal, sides convex. Protoconch rounded, smooth, of H whorls. 

 Whorls 5, slightly rounded, the last carinated at the periphery ; base 

 convex. Suture canaliculate. Aperture rhomboidal, oblique. Prri- 

 stomc with numerous irregular denticles, some of them extending far 

 into the shell. Columella oblique, arcuated, having a blunt tubercle 



