BY C. HEDLEY. 513 



G. BEDDOMEi, Petterd, MS. 



Reference s. — Journ. of Conch, iv. p. 150. Pioc. Roy. Soc. 

 Tasmania, 1888 (1889), table facing p. 86; 1890, p. 145. Vic- 

 torian Naturalist, Vol. x. Dec. 1893, p. 148, right engraving. 



From the preceding this hitherto uncharacterised species may- 

 be distinguished by attaining one-third larger dimensions, by its 

 mahogany colour, by its wider and more rounded aperture, by the 

 more posterior position of the orifice of the primary shell, and by 

 that shell being affixed to the secondary more in the plane of its 

 greatest length, at about an angle of 25° to the median line. 

 Length i^, breadth 3, height 1 mm. 



Type in Mr. Petterd's collection. 



This species has only been found in South Tasmania. It was 

 collected by Mr. Beddome in a quarry hole at the old station near 

 his residence at Hillgrove. Recently I have received from Mr. 

 Beddome two half-grown Gundlachia, which I identify with this 

 species, collected by his friend Mr. May near Sandford, Tasman's 

 Peninsula. 



In asserting that this species is indistinguishable from ^yetterdi, 

 Johnston is inaccurate. That differences are to be discerned I 

 hope to have shown by drawings aad descriptions. It is possible 

 that the future may produce forms linking one to the other, but 

 our present knowledge is confined to the inhabitants of a few tiny 

 pools and is insufficient to discuss the fixity or flexibility of their 

 specific features. 



Conclusion. — The genus Gundlachia contains four American — 

 G. ancyliforinis, tneekiana, californica, Grepiduli7ia — and two Aus- 

 tralian species — G. petterdi and heddomei. It is nearly allied to 

 Ancylus, from which it differs anatomically by a distinct pattern 

 of radula, and conchologically by its compound shell. The 

 existence, variously affirmed and denied, of a jaw is now demon- 

 strated by figures. It has been suggested, but not proved, that 

 in unfavourable circumstances the shell never attains its compound 

 development, but remains simple. From an Ancylus of the same 



