33 GASTEROPODA. 



DILOMA. 



Sub-globose, smooth, imperforate ; whorls convex ; mouth rounded ; 

 columella prolonged in front, and extending over the umbilicus ; oper- 

 culum multi-spiral. 



16-1. D. nigerrima, Linncens, p. 466 ; Trochus melanostomus, 

 Desliayes, Anim. sans vert., ix., p. 157. Purplish black, lightly spirally 

 striated, interior white, iridescent. Length, '55 ; breadth, '85. 



Both islands. Chatham Islands. 



THALOTIA. 



Conical, turreted, solid, granulated ; imperforate ; mouth longer 

 than wide ; columella sub-truncate, tubercular ; outer lip thickened 

 and crenulated within ; operculum multi-spiral. 



Australia and New Zealand (Gray). 



I have not been able to find the name of the species said to come 

 from New Zealand. 



ZISYPHINUS. 



Trochiform, conical, imperforate ; body whorl angular ; mouth 

 quadrangular ; columella simple, sometimes terminated by a tooth. 



165. Z. tigris, Martyn; Troclius granatum, Laniark, I.e., is.., p. 

 145. Bather solid ; body whorl ventricose, not much angled, with fine 

 spiral moniliform lines, about eighteen to twenty-five on the body 

 whorl in front of the mouth, from the suture to the keel; columella 

 with a small callosity over the umbilicus. Chestnut, more or less 

 marbled with white. Length, 2'13 ; breadth, 2'5 ; angle of spire, 75. 



Cook Strait. Chatham Islands. 



166. Z. selectilS, Chemnitz. Like the last, but the spiral monili- 

 form lines are further apart, about ten on the body whorl in front of 

 the mouth, from the suture to the keel, and the beading is larger. 

 Purplish chestnut, varied with darker, often forming a row of spots at 

 the suture. Length, 14 ; breadth, 15 ; angle of spire, 75. 



Cook Strait. 



167. Z. eunningliami, Gray. Thin, whorls flattened ; suture 

 obscure ; body whorl much angled with fine spiral rnoniliform lines, 

 about ten on the body whorl before the mouth, from the suture to the 

 keel, beading much smaller than in the last ; columella with a large 

 callosity over the umbilicus. Pinkish white, with reddish purple dots 

 on the ribs ; base nearly white. Length, 1 35 ; breadth, 2'2 ; angle of 

 spire, 85. 



Common. 



In the young the body whorl is less sharply angled ; there is often 

 a row of purple spots round the suture, and the base is ornamented 

 with interrupted pinkish brown lines. 



* 168. Z. Spectabilis, Adams. Shell regularly conoid, rather 

 ponderous ; whorls slopingly convex, grain ridged ; ridges rather 

 distant, grains large, interstices between the ridges smooth, excavated, 

 flesh-colour, or yellowish ; ridges dotted with pinkish red. (Reeve.} 



