228 CLASS III. GASTEROPODA. ORDER VII. PECTINIBRANCHIATA. 
ford to separate such as have their shells umbilicated under the new title 
of Perdrix (Latiné Perdiz) ; this, however, failed on account of the great 
variableness and insignificance of that character ; the presence or absence 
of an umbilicus depending either upon slight variation in the volution of 
the whorls, or upon the direction of the last effusion of enamel from the 
chance of its filling it up. Another and more meritorious endeavour to 
reduce the genus Dolium is one lately proposed by Valenciennes, in which 
he separates, under the new title of Malea, all those species which may be 
considered intermediate in their characters between the Dolia and the 
Cassides (Dolium pomum, Dolium latilabre*, e.g.) on account of the lip 
of their shell being thickened. 
The anatomy of the Dolia has been described and figured for the first 
time by Quoy and Gaimard in the ‘ Zoologie’ of the ‘ Voyage de l’As- 
trolabe.’ 
The shell of Dolium may be described as being thin, rotundately oval, 
and very ventricose or inflated, terminating at the base with a very short, 
posteriorly reflected canal; the spire is short, and the whorls are gene- 
rally ribbed transversely (transversely as regards the shell, but longitudi- 
nally as regards the whorl), the last whorl forming an umbilicus occa- 
sionally, or at different periods of growth; the aperture is large, the 
columellar lip thin, and somewhat widely expanded, and the outer lip for 
the most part either fimbriated or crenated. The Dolia, like the Harpe, 
are not provided with any operculum. 
Examples. 
Pl. CCLXIV. Fig. 1. 
Do.ium oLEeARiuM, Lamarck, Anim. sans vert., vol. vil. p. 259. Kiener, 
Iconographie des Coquilles vivantes, pl. 1. f. 1. 
* In proof of our better estimation of the genus Ma/ea of Valenciennes, it is only necessary 
to show the confusion that has attended this species. Thougha species comparatively new, it 
has been yet referred to no less than four different genera by living authors, viz. Cassis rin- 
gens, Gray, Buccinum ringens, Wood, Malea latilabris, Valenciennes, and Dolium latilabre, 
Kiener. For our own part, we prefer Mr. Gray’s arrangement, and we believe that the Malee 
of Valenciennes are generally referred to the genus Cassis. 
