MANGILIA. 



57 



costate ; the whole surface of the whorls is spirally striated, but not 

 so conspicuously between the angulation and the suture ; the latter 

 is marginate. Aperture small and narrow ; inflated towards the 

 middle ; outer margin produced, arcuate ; deep, broad sinus in 

 the proximity of the suture; inner margin curved, enamelled, with 

 a posterior callosity ; umbilicus very small ; anterior canal small, 

 almost truncate. 



Dimensions. — Length 15-5 mm. ; breadth 4"5 mm. ; length of 

 aperture 5'5 mm. 



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



G. 4221. An adult specimen. Presented hy John Dennant, Eaq. 



Genus MANGILIA (Leach MS.), Eisso {em.). 



I [Hist. Nat. Eur. Merid. t. iv. 1826, p. 219.] 



Bda (Leach MS.), Gray, Proc. Zool. Soc. 1847, p. 13-1. 

 Shell fusiform, not perforated ; aperture commonly narrow, with 



a short truncated canal ; inner margin varicose ; sinus near the 

 suture. Typically the shell is longitudinally costate. It is 

 usual to include species with a well-marked, deep sinus ; the type 

 of the genus, however, has a mere curvature as a sinus. In regard 

 to Bela, see p. 60. 



Ti/pe. — Mangelia costulata, Eisso. 



Mangilia obsoleta, sp. nov. 



[PI. Ill, Figs. 9«-Zi.] 



Shell small ; protoconch composed of two smooth turns, deeply 

 umbilicated ; whorls four and a half to five in number, spire-whorls 

 short, subangulate not far from the suture, oblique costae not very 

 prominent and becoming obsolete on the anterior portion of the 

 body-whorl ; the latter is very large in proportion to the size of 

 the shell ; spiral strife not prominent, equidistant, more numerous 

 between the peripheral subangulation and the suture. Aperture 

 elongate ; outer margin curved, slightly varicose, with an elevated 

 deep sinus, also varicose, near the suture; columellar margin 

 covered with a thin deposit of smooth callus; canal short. 



This is by no means a typical Mangilia ; but for the absence 



