848 



Nucula atkinsoni, Johnston (sp.). 



1881. Portlandia atkinsoni, Johnston, Pap. Roy. Soc. Tas. 1880, p. 39. 

 1886. Nucula atkinsoni, Tate, Trans. Eoy. Soc. South Aust. vol. viii. p. 127, 



pi. iv. figs. Za-c. 

 1893. Nucula atkinsoni, Tate and Dennant, id. vol. xvii. pt. 1, p. 224. 

 1896. Nucula atkinsoni, Pritchard, Proo. Eoy. Soc. Vict. vol. viii. n.s. p. 147. 



Much smaller than N. tenisoni, it may be distinguished from 

 that species by the crenulated margin, and the tessellated sculpture 

 of the exterior, in which the concentric lineations are the most 

 prominent ; ligament pit relatively smaller. 



Dimensions. — Height 6 mm. ; length 7 mm. 



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



L. 9828. Examples of both valves. Furcliased. 



Family NUCULANID^. 



Genus NUCULANA, Link. 



[Besch. Rostock, Abth. iii. 1807, p. 155.] 

 Leda, Schumacher, Essai Nouv. Syst. Habit. Testaces, 1817, p. 173. 



Differs principally from Nucula in being more or less produced 

 and angulate in front, the surface is concentrically or obliquely 

 ridged, and carries a well-defined keel curving from the umbo 

 to the rostrate prolongation. The cardinal border is slightly 

 angulate, hinge teeth numerous ; pallial line sinuous. 



Tyjie. — Area rostrata, Linnaeus. 



Nuculana vagans, Tate (sp.). 



1880. leda lucida, Tenison-'Woods, Proc. Linn. Soc. N.S.W. vol. iv. p. 3, 

 pi. i. fig. 6 [non Loven). 



1886. leda lucida, Tate, Trans. Roy. Soc. South Aust. vol. viii. p. 131, 



pi. vi. figs, la-b {non Loven). 



1887. leda vagans, Tate, id. vol. is. p. 188. 



1893. leda vagans, Tate and Dennant, id. vol. xvii. pt. 1, p. 224. 



Shell solid, subveutricose ; umbones small, very slightly directed 

 posteriorly; anterior side rounded, posterior rostrate; ventral 



