12 SCAPHANDER. 



Dimensions. — Lengtli 10 mm.; breadth 3 mm.; length of 

 aperture 4 mm. 



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



G. 9307. Two specimens. Purchased. 



Family SCAPHANDRID^. 



Genus SCAPHANDER, Montfort. 

 [Conch. Syst. t. ii. 1810, p. 335.] 



This genus may be readily distinguished from Bulla and 

 Bullinella by the enormous capacity of the body-whorl, which 

 is much dilated anteriorly ; there exists no columella properly 

 so-called, the whorls not being in contact with each other. 



Type. — Bulla lignaria, Linn. 



Scaphander tenuis, sp. nov. 



[Plate I. Figs. 4(j-(;.] 



Shell with small but deep apical umbilicus ; spirally striated, 

 the striae frequently being regular and equidistant over part of 

 the surface and closing in antero-posteriorly, farthest apart in the 

 median portion of the whorl, closest together towards the apex ; 

 lines of growth conspicuous on the smooth exterior and in the 

 thin spiral grooves, causing the latter to assume a minutely 

 punctated appearance ; aperture extending the whole length of 

 the shell, constricted posteriorly, expanded, curved, and produced 

 anteriorly; inner margin furnished with a conspicuous and slightly 

 reflected smooth band ; in consequence of the thinness of the shell, 

 both striae and lines of growth are seen in the polished interior of 

 the aperture. 



Mr. John Dennant, in giving ' a list of species of mollusca found 

 in the Muddy Creek beds, alludes to a MS. species of Professor 

 Tate as Scaphander fragilis. As that has, apparently, neither been 

 figured nor described, the present writer is unable to state in what 

 way it may be related to this species. 



1 Trans. Eoy. Soc. South Aust. vol. xi. 1889, p. 48. 



