LENTALItTM. 293 



Dentalium. aratum, Tate. 



1887. BenlaUnm aratum, Tate, Trans. Roy. Soc. South Aust. vol. ix. p. 192, 



pi. XX. fig. 8. 

 1893. Dentalium aratum, Tate and Dennant, id. vol. xvii. pt. 1, p. 223. 

 1895. Dentalium aratum, Tate and Dennant, id. vol. xix. pt. 1, p. 112. 



Shell small, slightly curved, furnished with seven or eight bold 

 longitudinal ribs, between which are several minute longitudinal 

 striae crossed by conspicuous lines of growth. 



This species was, apparently, without a posterior fissure, and 

 would be regarded as a typical Dentalium. Although small, the 

 shell is solid, and forms no exception to the rule that solidarity 

 is accompanied by frequent repairs to the shell. When broken, 

 it will be seen that the hard internal layer tends to form a tube, 

 which would probably lead some authors to classify it with the 

 genus Antale ; but, as previously remarked, such tube is of little 

 or no systematic value. 



Dimensions. — Length 22mm.; width of anterior aperture 2'5mm. 



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



G. 9386. Several specimens. Furchased. 



Dentalium mantellL, Zittel. 



18-50. Dentalium, sp. nov., Mantell, Quart. Journ. Geol. Soc. vol. vi. p. 331, 



pi. xxviii. fig. 15. 

 1865. Dentalium mantelli, Zittel, Eeise der Novara, Palaontologie, Bd. i. 



Abth. ii. p. 45, taf. xiii. fig. 7. 

 1873. Dentalium mantdU, Hutton, Cat. Tert. MoU. X.Z. p. 1. 

 1873. Dentalium tenuis, Hutton, id. p. 1. 

 1873. Dentalium irregularis, Hutton, id. p. 1. 

 1876. Dentalium kicksii, Tenison-Woods, Pap. Eoy. Soc. Tas. 1875, p. 15 



{non Nyst. 1843). 

 1878. Dentalium Icickii, R. Etheridge, jun.. Cat. Aust. Foss. p. 162. 

 1887. Entalis mantelli, Tate, Trans. Roy. Soc. South Aust. vol. is. p. 190. 

 1893. Entalis mantelli, Tate and Deunant, id. vol. xvii. pt. 1, p. 223. 



1895. Entalis mantelli, Tate and Deunant, id. vol. xix. pt. 1, p. 112. 



1896. Entalis mantelli, Pritchard, Proc. Roy. Soc. Vict. vol. viii. n.s. p. 126. 



This species differs from D. aratum in being larger, having more 

 numerous longitudinal costse of variable size, crossed by frequent 

 and conspicuous lines of growth, and especially by the possession 

 of a rather long and wide posterior fissure. This is a common 

 species in the older Tertiary of Australasia. 



