82 MAEGIiVELLA. 



Family MARGlNELLIDiE. 



Genus MARGINELLA, Lamarck. 



[Mem. Soc. Hist. Nat. Paris, 1799, p. 70.] 



Shell oval or jblong; smooth; spire short, sometimes incon- 

 spicuous ; outer margin frequently thickened and dentate ; 

 columella plicate ; aperture slightly canaliculate anteriorly. 



Type. — Valuta glabella, Linnaeus. 



Marginella wentworthi, Tenison-Woods. 



1877. Marginella weniworthii, Tenison-Woods, Pap. Roy. Soc. Tas. 1876, 



p. 109. 



1878. Marginella wentworthii, E. Etheridge, jun., Cat. Aiist. Foss. p. 165. 

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



p. 92. 



1888. Marginella wentworthii, Johnston, Geol. Tasmania, pi. xxxi. figs. 5, 5a. 



1889. Marginella wentworthi, Dennant, Trans. Eoy. Soc. South Aust. 



vol. xi. p. 43. 

 1895. Marginella wentworthi, Tate and Dennant, id. vol. xix. pt. 1, p. 111. 



Protoconch composed of a globose, obtuse, smooth turn, barely 

 distinguishable from the succeeding whorl. Shell small', elongate, 

 and polished ; spire moderately elevated ; whorls five in number 

 in adult specimens, convex, body-whorl obtusely angulate at the 

 periphery, surface longitudinally striated by lines of growth, and 

 obscurely spirally lineated, suture accompanied by an anterior 

 spiral depression ; aperture elongate, somewhat inflated towards 

 the middle ; outer margin thickened, furnished with a number of 

 small crenulations terminated posteriorly by a rather large denticle, 

 or tubercle, behind which is a broad, slightly canaliculate depres- 

 sion ; inner margin with four prominent plications ; anterior 

 portion of the aperture widely channelled. 



This species resembles M. contahulata, Deshayes, from the 

 Middle Eocene of the Paris Basin ; but the latter is more lanceo- 

 late, is minus crenulations on the inner side of the outer margin, 

 and has bifid and divergent plications. 



Dimensions. — Length 7 mm. ; breadth 4 mm. ; length of aper- 

 ture 4 mm. 



