﻿MOLLUSCA.- MEDLEY. IO-> 



gradate. Sculpture : On the base and spire are taint traces oi 

 radial sculpture. Along the suture runs a ('"ep groove 

 followed by a corresponding ridge. The remainder of the last 

 whorl is surrounded by a succession of numerous fine spiral 

 threads parted by equal grooves. Aperture subcircular, above 

 with the vestige of a varix, below a fold running from the 

 anterior edge of the mouth to the margin of the umbilicus, 

 edge of lip simple bevelled within, columella excavate. Base 

 rather flat. I'mbilicus narrow but deep, a sixth of the shell's 

 diameter. M;ijor diameter i '85, minor diameter r55, height 

 I *2 mm. 



This is smaller, flatter and more finely grooved than other 

 Australian species. 



Hah. — Numerous specimens were dredged in 100 fathoms 

 forty miles south of Cape Wiles, South Australia. 



RissoA HL'LLiANA, Tate, 



VAR. EUCRASPEDA, var. riov. 



(Plate xviii., fig. 21.) 



This deep-sea variety differs from the typical shore form by 



being pure white, slightly larger and comparatively broader, 



and by having fewer and more prominent radials. Thus it 



acquires a lip broader and more scalloped, approaching a 



varix. 



Hah. — Several specimens in 100 fathoms forty miles south 

 of Cape Wiles, South Australia. 



RissoA LOCKVERi, sp. nov. 

 (Plate xviii., fig. 22.) 



Shell small, rather thin, ovate-conical, imperforate. Colour 

 white. Whorls four, of which the two first are sharply 

 marked off as the protoconch. Sculpture : On the shoulder 

 is a smooth, unbroken slope, succeeded by elevated, widely- 

 spaced spiral keels, of which the last whorl bears eight and 

 the penultimate three. On the earlier whorls are numerous 

 fine spiral striae. The interstices of the keels are engraved 

 with close radial scratches. Aperture subcircular, lip slightly 

 expanded. Behind the columella is a narrow axial crevice. 

 Length 2, breadth 1*3 mm. 



The species is named in honour of Mr. N. Lockyer, Comp- 

 troller of Customs, under whose auspices these collections 

 were made. It is related to R. imhrex,^ than which it is 

 smaller, broader in proportion, and possesses more spirals. 



Hah. — Numerous specimens were taken in 100 fathoms 

 fortv miles south of Cape Wiles, South Australia. 



1 Iledley— Proc. Linn. Soc. N.S. Wales, xxxiii.. 1908. p. 469. pi. x.. f. 33. 



