118 RECORDS OF THE AUSTRALIAN MUSEUM. 



PSEUDORISSOINA CAPITICAVA, Sp.ltOV. 



(Plate xxiii., figs. 12, 13). 



Shell slender, elongate, diaphanous, smooth, constricted at the 

 suture, and thus conveying a nodose expression to the spire. 

 Colour white. Whorls six, exclusive of the protoconch, margined 

 at the suture. The heterostroph? apex of this genus is more 

 complex than was at first supposed. The early whorls are 

 concealed by the later, and the vertex of the shell is a whorl 

 which rises as an arch and encloses the protoconch in a hood. 

 It may be that the first whorls are not merely wound at right 

 angles to the adult, but are completely reversed by rotation 

 through ninety degrees. Aperture subtriangular, channelled 

 above, effusive below, outer lip thickened, inner lip with a 

 distinct callus deposit. Length, 4*4; breadth, 15 mm. 



Several specimens. This is closely related to P. tasmanica, 

 Tenison Woods, but the novelty is a narrower shell, with an 

 additional and more inflated whorls. 



Septa petulans, sp.nov. 

 (Plate xxiii. . fig. 14). 



Shell small, conical, produced. Whorls asymmetrically swollen, 

 six remaining on the type. Our material does not present a 

 complete apex. Colour cream, with rusty irregular scattered 

 dashes. Sculpture : seven varices, being at the rate of about 

 one to two-thirds of a whorl, between these slight radial plica- 

 tions raise the larger threads into low tubercles, interstices 

 microscopically transversely striated. The spirals consist of tine 

 revolving threads parted by shallow interstices, sixteen on the 

 penultimate, and about thirty-five on the last whorl. Here and 

 there, especially on the base, the threads tend to be alternately 

 larger and smaller, while a few of the peripheral threads stand 

 out more conspicuously than the rest. ApertXire perpendicular, 

 ovate, a conspicuous tubercle in the posterior angle. . Anterior 

 portion of the columella crossed by several transverse wrinkles. 

 Outer lip faintly dentate within. Canal short and broad. Length, 

 35 ; breadth, 1 4 mm. 



Several broken shells were dredged, but our figure and descrip- 

 tion is based on a dead shell gathered by one of us (May) on the 

 beach at Pirate's Bay, near Cape Pillar. 



Dr. Dall tinds in the radula generic distinction between Sejrta 

 and Cymatium. We associate our species with the former from 

 the gezieral resemblance it bears to 8. tritonis, Linne. 



