55 



hood of Paris : O. canaUfera, O mitreola, and O. Laumontiana. Shells of 

 this genus, but not in a state to allow of their species being determined, 

 are also found in the Vincentine territory. 



XIII. Ancilla, An oblong subcv'indrical univalve, with a short spire, 

 not channeled : the aperture efiused, and its base slightly notched. A 

 thick oblique fold at the base of the columella. 



The separation of these shells from those of the genus Olivet, appears 

 to be hardly necessary ; the only material difference being, that those 

 which he places under the latter genus have not the turns of the spire 

 separated by a channel, as is the case with those which are allotted to 

 the former genus. Four species of these shells are found at Grignon. 

 and Courtagnon : A. buccinoides, A. subulata, A. olivula, and A. ca- 

 nalifera. 



The characteristic of the genus Voluta, of Linnaeus, the folded colu- 

 mella, is doubtlessly much too general, and belongs to many shells 

 which require to be arranged under separate genera. Bruguiere, in 

 the first place, separated those shells which were not notched at their 

 base : since which, Lamarck has taken from this Linnaean genus such 

 shells as appeared to him to be capable of forming the new genera, 

 mitra, colombella, marginalia, cancellaria, and turbinclla. 



XIV. Voluta. An ovate subventricose univalve; the apex papillary, 

 and base emarginated. The columella plicated : the inferior plicae 

 being largest or longest. 



In this genus are comprised, Voluta Cithara, Lam. Encyc. T. 384, 

 Fig. \.\-Citharadits, Chemn. Vol. xi. p. 297, Tab. 212, Fig. 2098, 

 2099 This shell is remarkable for the beautiful polish which; it retains. 

 V. Spinosa, Lam. ; S trombus Spinosus, Linn. ; S. luctator, Brand, Foss. 

 Fig. 65, List, Tab. 1033. This shell is singularly beautiful, retaining 

 not only its perfect form and its polish, but its orange-coloured trans- 

 verse stripes, V. Mwcialis, Lam. is Sir. luctator, Brand. Fig. 65. In 

 V. muricina and V. Costaria, of Lamarck, is instanced the ambiguity so 

 frequently observable in fossil shells : the general form of murex in the 



