222 
cylindric ; upper volutions extremely small and scarcely 
defined by the suture. the apex obtuse ; aperture narrow, 
nearly extending the entire length of tae shell and 
spreading a little at the base; outer lip thin; pillar 
with four strong folds. %...4. Tenby, very rare. 
TripE.—INVOLUTA. 
Shell destitute of a canal, but having the base of the 
aperture effuse or notched and its whorls so com- 
pressed and convolute that the last almost or entirely 
conceals the rest. 
Genus.—OVULA. 
Turgid, attenuated at each extremity, subacuminated ; 
margins convolute ; aperture longitudinal, narrow, 
effuse at the extremities ; pillar lip toothless. 
O. Paruna. Sow. in Z. J, 4. p. 161.—Buuta P. 
Pen. 4. p. 117. t. 70. f. 85a— Don. t. 143.—Mont. 
p. 207.—Lin. T. 8. p. 121.—Dor, Cat. p. 43. t. 12. 
Sf. 8.—D. p. 475.—Votva P. F. p. 331.—Oblong, 
smooth, white, pellucid, the upper end extending beyond 
the body, the base more extended ; aperture large, ter- 
minating in a short canal at each end, most contracted 
at the top; columella twisted, forming a subumbilicus ; 
outer lip plain and very acute. 4...1. Weymouth. 
