290 



WHORL. 



which are rich in colouring. Cymba and Melo have been se- 

 parated by Mr. Broderip from the genus Voluta of Lamarck, 

 for reasons stated in their respective descriptions. Fig. 443. 



VOLVARIA. Lam. (Volva, a shuttle.) Fam. Columellaria, Lam.— 

 Bescr. Cylindrical, convolute, spirally striated ; spire very 

 short, nearly hidden ; aperture narrow, as long as the whole shell ; 

 columella with three oblique plaits; outer lip dentated. — Obs. 

 The Volvaria are only known in a fossil state, and resemble some 

 species of Bulla in general form, but are distinguished by the 

 plaits on the columella. Fig. 439, V. concinna. 



VOLUTELLA. Sw. {A little volute.) A genus composed of those 

 species of Ma rginella, Auct. which have the spire concealed, 

 and the aperture smooth within. Fig. 438, Persicula of Schu- 

 macher. 



VOLUTILITHES. Sw. {Voluta, and \idog, lithos, a stone.) A 

 genus composed of some fossil species of Voluta, which have the 

 plaits on the pillar generally numerous, indistinct, and some- 

 times wanting altogether, with a pointed spire. Fig. 436, V. 

 spinosa. 



VOLUTION. See Whorl. 



VORTICIALIS. Lam. A genus of microscopic Foraminifera. 



VULSELLA. Lam. (A little tongue.) Fam. Ostracea, Lau. 

 Margaritacea, BL— Descr. Equivalve, irregular, longitudinal, 

 compressed, oblong ; umbones separated by a slight area in both 

 valves ; hinge with a large pit in the centre, containing the 

 cartilage, the ligament being spread over the areas ; muscular 

 impressions, one on each valve, sub-central, oblong. — Obs. This 

 genus differs from Ostreea in the equality of the valves, and in 

 having a hollow pit in the hinge for the cartilage. Vulsella lin- 

 gulata, fig. 185. 



WATERING-POT. Aspergillum, fig. 44, commonly so called on 

 account of the resemblance of its perforated termination to that 

 of the spout of a watering-pot. 



WENTLE TRAP. Scalaria pretiosa, commonly so called. 



WHORL. A complete turn or revolution round the imaginary axis 



