84 F. B. Meek on Acteonide. 
cast onepeee from a young specimen of this latter species. 
In the 12th Annual Report of the Regents of the University 
of New York, Mr. Hall describes his genus Leptocelia, but, mis 
ided by an ‘imperfect specimen, he gives us an incorrect ‘dé 
about the form of the crura, which are in reality spirals, with 
three or four loose outward-turned volutions, 
Some distance from — origin, the crura are divided into an 
exterior branch, which is spiral, and an interior, which, 
running obliquely towards the fron 
ends inward and unites itself with the oppo- 
site branch. At the bend the angle projects as 
a! ttle horn 
I shocleed this organization in Reyne 
specimens of Leptoceelia concava, —. * 
fectly similar structure is also found in Lore ees se 
bratula lepida, Goldfuss. Specimens of the lat- “Yeptocelia aoncava. 
ter are found in the Hifel. Leptoceelia concava ao upp aaa 
is frequently found in our — ie ers, fie ei us ated crea int < 
he annexed figure is a specimen of Lept. © upp 
concava from which the shell has ‘ieun removed, the renee side 
being directed upwards. 
Ann Arbor, Mich., Dee. 1862. 
cence 
Art. XITV.—Remarks on the family Acteonider, with i i! 
of some new genera and sub-genera; by F. B. MEE 
TuE family Acteonide, established by d’Orbigny, is a group 
much interest to the Paleontologist and Conchologist, not 
rely in consequence of its comparative antiquity, and the 
epstiee and diversity of forms assumed by the "Find of its 
various genera, but also because it is, as it were, a ind of ie 
hetic group. That is to say, while the numerous 
belonging to its several genera exhibit characters tsdiating 
lations as members of the same family, they have pre 
ee particularly during the Jurassic and Cretaceous periods, 
