86 MAEGINELLA. 



impossible not to recognize the phenomena alluded to as mere 

 variations of individuals of one species. The protoconch, the 

 shape of the shell, form of aperture, the suture — in fact, every 

 other characteristic except the number of plications and the 

 occurrence of marginal crenulations — are identical in the forms 

 here retained in M. propinqua. 



Biinensiotis. — Length 12 mm.; breadth 5"5mm.; length of 

 aperture 9' 5 mm. 



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



G. 9339. A series exhibiting stages of growth. Purcliased. 



Marginella inermis, Tate. 



1878. Marginella inermis, Tate, Trans. Phil. Soc. Adelaide, 1877-8, 



p. 93. 

 1889. Marginella inermis, Dennant, Trans. Roy. Soc. South Aust. vol. xi. 



p. 43. 

 18'J5. Marginella inermis, Tate and Dennant, id. vol. xix. pt. 1, p. 111. 



Shell pyriform, attenuating anteriorly, smooth ; spire very short, 

 composed of from two to three whorls, body-whorl comprehensive, 

 extending almost the whole length of the shell, longitudinal growth- 

 lines conspicuous, suture well defined, polished ; aperture elongate, 

 broadly rounded posteriorly and slightly produced anteriorly where 

 it is widely channelled ; outer margin thickened and crenulated, 

 though comparatively smooth towards the posterior extremity ; 

 columellar margin furnished with four plications in the majority 

 of individuals, though one adult specimen in the Museum has 

 only three, and another three with the trace of a fourth. 



Its shape, the elongation of the aperture, and its rounded form 

 in the neighbourhood of the posterior sinus, serve to readily 

 distinguish 21. inermis from all other Australasian Marginella!, 

 Except for the dentated outer margin, this species might perhaps 

 be included in the subgenus Prunum. 



Dimensions. — Length 12 mm.; breadth 6*5 mm. ; length of 

 aperture 10'5 mm. 



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



G. 4207. Several examples of the adult. 



Presented hy John Pennant, Fsq. 



