263 



callous ; umbilicus not f uniculate, deep, and bordered by a tliin 

 expansion on the inner margin. 



Dimensions. — Length 21 mm.; breadth 19mm.; length of 

 aperture 16 mm. 



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



G. 4278. Examples of the adult. 



Presented hy John Dennant, Esq. 



G. 5529. Specimen having a narrow umbilicus and very thin 



inner margin. Purchased. 



G. 9406. Two specimens. Purchased. 



Subgenus SIGARETOPSIS, Cossmann. 

 [Ann. Soc. Roy. Malac. Belg. t. xxiii. 1888, p. 168.] 



The chief distinguishing features of this subgenus are the Tery 

 short spire, depressed form, immense umbilicus, and the absence 

 of a funiculus, whilst in front of the latter the columellar border 

 is thin and lamellose ; inner margin callous posteriorly. 



Type. — Natica ivfundihulum, Watelet. 



Natica (Sigaretopsis) subinfundibulum, Tate. 



1893. Natica {Sigaretopsis) siihinfundibuhtm, Tate, Trans. Roy. Soc. South 

 Aust. vol. xvii. pt. 2, p. 327, pi. s. fig. 11; pi. vi. fig. 6. 



Shell much depressed, spire very short, suture not cut in, 

 body-whorl enveloping ; lines of growth oblique, undulating ; 

 aperture ovate ; outer margin thin ; umbilicus very large, striated, 

 and open, displaying the spiral formed by successive whorls ; 

 posterior callosity of the inner margin not prominent. 



It is rather more conical in form than N. tnfundibuhim, Watelet, 

 the type of the subgenus, of the European Eocene, with which, 

 however, it is closely allied. 



Dimensions. — Length 15'5 mm. ; breadth 13 mm.; length of 

 aperture 1 1 mm. 



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



G. 9405. Examples illustrating stages of growth. Purchased. 



