NON-PULMONARY GASTEROPODS. 
423 
The animal has a large head, provided with two tentacles. The 
naouth terminates in a thick trunk furnished with hooked teeth. The 
Fig. 255. Ovula volva (Linneeus). 
foot is very large, furrowed in front, and projecting from all parts of 
the shell, hut without operculum. The Volutin live on the sands 
Rear the shore ; sometimes they are found high and dry, left by the 
retreating tide. Their shells, of various forms, are ornamented with 
the most lively colours, the surface covered with irregular lines, the 
tint of which is generally in strong contrast with that of the ground. 
Among the more remarkable species illustrated in Pl. XXIII., we 
may note : Fig. I., Yoluta undulata ; Fig. II., Valuta cymbium ; Fig. 
Ill, Valuta delessertii ; Fig. IV, Valuta musica ; Fig. V, Valuta im- 
perialis ; Fig. VI, Voluta scapha ; and Fig. VII, Voluta vexiUum. 
Besides the genus Voluta, naturalists range the kindred genus 
Oliva, so named from their resemblance in form to the olive. Their 
Pearly cylindrical shell is slightly spiral, polished, and brilliant as 
the Porcelains ; its opening is still long and narrow, strongly notched 
, Fig. 256. Oliva Fig. 25?. Oliva por- 
vvythrostoma (Lamarck). phyria (Linnaeus). 
Fig. 258. Oliva iri- 
sans (Lamarck). 
Fig. 259. Oliva Peru- 
viana (Lamarck). 
111 front, its edge columellar, swollen anteriorly into a kind of cushion, 
an d striped obliquely in all its length. 
