OLIVA volutella. 
$a 
Class Mollusca. Order Zoophaga. Lam. 
Genus Oliva. Lam. Sys. 7, p. 416, 
Specrric CHARACTER. 
Shell ovate-conic, mitriform; chestnut, the body whorl bluish; 
spire lengthened, acute; pillar with 6-7, slender, regular 
plaits. 
Oliva volutella. O. test@ ovato-conicd, subcwruled, ad spiram 
basimque luteo fuscaté; spird valde productd, acuta. Lam. 
Sys. 7, 1, p. 432. 
$$ —__—_ 
We are indebted to the Rey. Mr. Bulwar for our specimens 
of this elegant and highly interesting species, received 
by him from the American Isthmus. It varies much in the 
intensity of its colour, as may be seen from the above 
description, given by Lamarck, of examples procured by 
Baron Humbolt on the shores of Mexico, 
There are reasons for believing the genus Voluta, as de- 
fined by Lamarck, to be typical of a natural group, compris- 
ing the genera Mitra, Oliva, Ancillaria and Marginella, 
The obvious affinity between Voluta and Mitra need not 
be dwelt upon. The connexion of Mitra with Oliva, we 
noticed in describing Mitra oliveformis, at pl. 48 of our 
first series. This aflinity appears further strengthened by 
a shell in the late Tankerville Collection, especially re- 
corded by Mr. G. Sowerby, as ‘‘ remarkable for its resem- 
blance to an Olive.’ We regret not having seen this 
shell, but such an authority is fully sufficient. The group 
of Mitres, by which this transision appears effected, is 
that mentioned under the head of M7. bicolor (Mitra, PI. 1.) 
of this series. This little group has three relations ; one 
to the smooth Mitres (as MZ. pertusa), another to Cono- 
helix, and a third to the Olives: the species are all re- 
markable for the polished smoothness of the ir surface, for 
the total absence of the inner lip, and for the lower plaits 
of the pillar extending much beyond the aperture: these 
plaits, moreover, are generally five or six, and all very 
slender. The conchologist will perceive that nearly the 
only character wanting, to render this description applica- 
ble to an Olive, is the channelled groove round the suture, 
This character is added to the shell before us, which thus 
presents the first type of form in the present genus. Pro- 
ceeding to the more perfect Olives, we observe the spire 
becoming gradually shorter ; the vitrious deposition on the 
inner lip increased in thickness; the upper plaits on the 
Oliva. PI, 1, 
