156 GASTROPODA. [Aspidobranchia. 



lower than the aperture, outlines convex. Protoconch rounded, shining, 

 and quite smooth. Whorls 5, the last large and globular, the spire- 

 whorls somewhat rounded ; base convex. Suture well marked. Aper- 

 ture ovate, somewhat oblique. Outer lip thin and simple. Columella 

 arcuate, solid, thickened, and slightly reflected ; a callus extends 

 from the insertion of the outer lip to the columella, partially con- 

 cealing the narrow umbilicus. Operculum horny, consisting of about 

 2 rapidly increasing whorls. 



Diameter, 2-3 mm. ; height, 2-75 mm. 



Animal. Foot comparatively large, flat, and undivided ; tail 

 abruptly rounded ; head produced into a retractile muzzle, emarginate 

 anteriorly ; tentacles of medium length, expanding and uniting at 

 the base so as to conceal the posterior portion of muzzle ; eyes im- 

 mersed, and situate in the lower half of tentacles ; colour whitish 

 throughout. 



Jaws forming 2 irregularly ovate objects, united by a narrow 

 band ; they are dark in colour, and the surface, as it were, imbricate, 

 with scale-like markings. 



Dentition. The formula is 23 + 2 -I- 1 + 2 + 23. The teeth are ar- 

 ranged in numerous transverse curved rows, the rhachidian short and 

 broad, with 11 minute cusps ; the laterals elongated, with the apex 

 somewhat expanded and curved inwards, the first armed with 6 or 7, 

 the second with 7 or 8 minute denticles ; marginals about 23, having 

 a single rounded cusp, and becoming shorter as they proceed out- 

 wards. 



Type in the Wanganui Museum. 



Hah. Inner Harbour, Napier ; found in considerable numbers 

 around the margin of a brackish pool ; type (F. Hutchinson, jun.) : 

 Titahi Bay, Cook Strait. 



Genus 4. PSEUDOLIOTIA, Tate, 1898. 



Pseudoliotia, Tate, T.R.S. S.Aust., xxii, 1898, 71. Type: Cydostrema 

 micans, A. Ad. 



Shell somewhat like Liotia ; test thick and porcellanous ; aper- 

 ture oblique to the axis, its margin thickened ; umbilicus reduced to a 

 mere chink ; operculum horny, multispiral. 



It recalls Moelleria, which is differentiated by a calcareous oper- 

 culum. 



Distribution. Australia, Tasmania, and New Zealand. 



1. Pseudoliotia imperforata, Suter, 1908. Plate 34, fig. 5. 



Pseudoliotia imperforata, Suter, P. Mai. S., viii, 26, pi. 2, f. 14. 



Shell small, globose, imperf orate when adult, thick, spirally costate. 



Sculpture consisting of prominent nodulous ribs, the nodules rather 



low ; there are 2 ribs on the penultimate and 6 on the last whorl ; on 



the latter a small nodulous rib appears on the last half of the volution, 



