16 EINGICTTLA.. 



according to the presence or absence of denticulations on the outer 

 margin of the aperture, and with reference to the number and 

 disposition of the columellar plications. 

 Type. — Auricula ringens, Lamarck. 



Ringicula lactea, Johnston. 



[Plate I. Figs, ba-d.'] 



1880. Ringicula lactea, Johnston, Pap. Roy. Soc. Tas. 1879, p. 34. 

 1888. Ringicula lactea, Johnston, Geol. Tasmania, p. 239. 

 1893. Ringicula lactea, Tate and Dennant, Trans. Eoy. Soc. South Aust. 

 vol. xvii. p. 223. 



Mr. Johnston describes this species as follows : — " Shell white, 

 shining, minute, conical, sub-turreted, of about 6 rapidly increasing 

 ■whorls; whorls convex, ornamented by regular, distant, punctate, 

 spiral sulci, about 12 on last whorl ; under lens broad, distant, 

 obsolete, transverse lirae may be traced ; suture deeply impressed ; 

 columella abbreviate, with two thick, tortuous folds, the lower 

 being the larger ; aperture roundly notched posteriorly and 

 anteriorly ; outer margin thick and reflexed, forming a broad 

 varix continuous with the last tortuous fold of columella." He 

 does not give a figure of the shell, but the description agrees 

 generally with specimens in the Museum. It may be added that 

 beyond the two columellar folds alluded to, a third one exists 

 posteriorly, the direction of which is approximately at right angles 

 to the others, and, as seen in perfect specimens, it resembles a 

 " tooth." 



Some specimens from Muddy Creek are but veiy faintly striated, 

 the columellar callosity being thick and partly spread over the 

 body-whorl, from which it is sharply defined. The protoconch 

 of those from the locality mentioned is very small, composed of 

 a turn and a half, smooth and somewhat obtuse. 



R. lactea may be distinguished from the living R. denticulata, 

 Gould, of Port Jackson and elsewhere in Australia, in that the 

 latter is more tumid, the anterior canal is more deeply cut, the 

 columellar callosity being much drawn out, whilst the spiral 

 lineations are closer together. 



Dimensions. — Length 3^ mm. ; breadth 2 mm. 



Form, and Loc. — Eocene : Muddy Creek, Victoria. 



G. 9304. Three specimens. Ftirchased. 



