191 



Shell elongate, stoutish ; apex acute ; whorls about twelve, 

 convex, the uppermost whorls angulated medially, covered with a 

 bluish- black to grey epidermis beneath which the colour is 

 reddish ; suture distinct. Base convex. Aperture circular, 

 slightly angulated and effuse at the base of the columella ; 

 shining-black within ; outer lip thin and arcuate ; columella 

 arched, obliquely excavated so as to form a slightly-raised border 

 exteriorly. Operculum circular and multispiral. 



Ornament consisting of depressed spiral threads, five or six on 

 the penultimate whorl, and of slightly-arched plicte (from eleven 

 to fifteen on penultimate whorl) which terminate abruptly at the 

 second lira from the anterior suture ; the lir?e as they pass over 

 the plica? produce nodular crenatures ; the whole surface is 

 sculptured with fine arcuate striae. The plicae vary much in 

 strength, rarely obsolete ; in the latter case the shell approxi- 

 mates to B. Laivleyaaum, from which it is conspicuously 

 distinguished by its elongate form, less dense, and more thread- 

 like spiral ornament. The base is concentrically ridged and 

 transversely striated. 



Dime7isions. — Of a large specimen, length 22, major diameter 

 of base, 5 ; of a medium-sized specimen, length 17, major 

 diameter of body-whorl, 4-5. The proportion of length to the 

 basal diameter varies from 100 to 22-5 to 100 to 33; but the 

 extremely-broad forms are rare. 



Habitat. — Living on the mud, between tide-marks, Port 

 Adelaide Creek ; Franklin Harbour ; in shallow water on 

 Zoste7'(S in Lake MacDonalcl, West Coast. 



Affinity. — The plicate ornament without distinctive granula- 

 tion reduces the comparison of this species to a very few 

 congeners ; but the non-plicate supra-sutural area, the number of 

 the spiral lirae and the elongate form separate it from all of 

 them. 



TOPinia fOVeolata, -ipec. nov. PI. i., lig. 13-13a. 



Shell small, depressed, slightly convex, semitransparent-white ; 

 whorls of rather slow increase, four, separated by an impressed 

 suture, but not conspicuously channelled. Last whorl angulated 

 at the periphery ; base rounded, profundly and widely umbilic- 

 ated. Aperture quadrately rounded. 



Ornatnent of penultimate whorl consisting of four spiral rib- 

 lets (of Avhicli one in the anterior-third is the strongest), and 

 slightly-oblique transverse threads (nearly as stout as the largest 

 of the spirals) ; the intersection of the spiral and transverse 

 threads produce rhombic pits, within which are a few spiral 

 stria? ; the largest spiral riblet is delicately granulated at the 

 intersections with the transverse threads. The body-whorl has a 

 gemmulated keel, the medial portion of the u^Dper surface has two 



