BY C. HEDLEY. 509 



G. PETTERDi, Johnston, 1879. 



S y n o n y m. — woodsi, Johnston, 1879. 



R ef e rences.— Proc. Roy. Soc. Tasmania, 1878 (1879), pp. 

 23, 25 ; 1884 (1885), p. 216 ; 1888 (1889), pi. . ff. 2a, 2b, 2c 

 (shell and animal), and table facing p. 86. Journ. of Conch, i- 

 1878, p. 400; ii. 1879, pp. 87, 137 ; iv. 1883, p. 150. Conch. 

 Cab. Band i. Abth. vi. Ancylinse, p. 73, t. 9, f. 8 (3 figures of 

 shell, poor). Victorian Naturalist, Vol. x. Dec. 1893, p. 148, 

 left engraving. 



Shell (ff. 1-3) consisting of two portions, which I will refer to 

 as the primary and the secondary shell respectively. The primary 

 may not be called the " larval " shell, that term being already 

 appropriated to the shell of the veliger phase. Primary shell 

 elliptical, above patella-shaped, beneath flat, attached to the 

 secondary shell for three-quarters of its length and, as viewed 

 from above, affixed thereon at an angle of 35°. Secondary shell 

 regularly ancyliform, aperture squarely oval, straight-sided, and 

 wider before than behind. 



Sculpture : tiie primary shell is concentrically marked by 

 numerous raised growth lines, sometimes, not always, by weak 

 raised radiating hair lines. The secondary shell is also orna- 

 mented by raised concentric growth ridges, about a dozen of the 

 earlier of these are stouter, the later fainter and closer together. 

 These incremental lines are widest apart at the right anterior 

 corner, showing a tendency in the shell towards spiral growth. 

 Sometimes weak radiating ridges also occur. Under a low power 

 the whole external surface appears shagreened ; this I believe is 

 owing merely to the tattered condition of the epidermis. 



Colour : the shell itself is nearly transparent and colourless, the 

 epidermis is thick and black, giving to the })rimary shell a dull 

 black and to the secondary a grey aspect ; the stouter concentric 

 ribs of the secondary shell are an ochreous-yellow. 



Viewed from beneath, the whole of the primary shell is visible, 

 seen either through the substance, or projecting beyond the edge, 

 of the secondary shell. The primary communicates with the 



