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XL. Delphinula. A subdiscoidal, or short conical, solid, pearly, 
umbilicated univalve, with rather rough turns. The opening round ; 
the margin circular and uninterrupted. 
This genus is formed of shells, which were included by Linnaeus in 
his genus Turbo ; a genus which he formed merely on the character 
of the complete roundish opening of the shell. Lamarck, for the sake 
of greater accuracy of distinction, has separated from this genus those 
shells, in which the two edges of the opening are circularly united ; 
and has left to the genus Turbo only those sea shells, which, pos- 
sessing a rounded opening, have the two edges of the opening con- 
stantly disjoined near the columella. With the shells which have been 
thus withdrawn from the genus Turbo, he thought it necessary to 
form the genera turritella , scalaria, pupa, and cyclostoma. But even 
thus, some confusion would exist ; since cyclostoma would contain 
both sea shells and land shells. To avoid this, the present genus is 
formed for the reception of the sea cyclostoma, whilst the land cyclos- 
toma are all reserved for the genus so named. In the delphinulae the 
edge of the opening is not reflected outwardly, nor is the point of the 
columella visible. 
Turbo testa umhilicata convexa, aufractibus, teretibus striatis : 
striis crenulatis incequalibus. Apertura omnino orbicularis. Foss. 
Hunt. Tab. i. Fig. *] and 8, may be taken, as exemplifying this genus. 
I am not acquainted with another British fossil of this genus ; whilst, 
of those found in the environs of Paris, Lamarck enumerates eight 
species : D. calcar, D. lima, D. conica, D. turbinoides, D. margi- 
nata, JD. striata, 1). sulcata, D. canalifera. 
With respect to the fossil shells to which I now call your attention, 
I must acknowledge my inability to determine precisely in what 
genus they should be placed. Their characters, however, approach- 
ing the nearest to those of this genus, I have placed them here, until 
more illustrative specimens have pointed out for them a more appro- 
priate situation. 
