DX7Jn)RY GASTEROPODA. 33 



Our specimens have a very smooth and glistening surface, and 

 show maikings similar to those of D'Orbigny's figures. That 

 they are in the state of casts is shown by the shell remaining on 

 part of the last whorl ; it is thin however so that it does not hide 

 the keels: in* this condition it has more the appearance of 

 T. Mosce, D'Orb. from the Coralline Oolite of France (Meuse). 



We have figured our specimen in this condition. 



This latter may probably be only a synonym. 



JSTone of o.ur specimens show whether there is an umbilicus, 

 being more or less imbedded in the matrix. 



There are five specimens in the Museum. 



Locality — Dundry. Inf. Ool 



TEOCHrS l^IOETENSIS, D'Orbigny. 



1850 T. Mortensis, D'Orb. Pal. fr. Terr. Jur. 2, Gast. 



pi. 315, figs. 5—8, p. 282. 



1867 Laube. Gast. von Balin. pi. 2, figs. 



6, p. 10. 



There are in the Museum two specimens which agree precisely 

 with D'Orbigny's description. The French locality given is from 

 the Inferior Oolite (Bajocien) of Niort. 



Locality — Dundry. Inf. Ool. 



TROCHrS IBBETSOITI, Morris and Lycett. 



1854 T. Ibbetsoni, Lye. and Morr. Gt. Ool. Moll. 

 Univalves, pi. 10, fig. 4, p. 62. 



"We refer provisionally here certain specimens which agree in 

 form with the description of the above species. But the texture 

 and aspect of the shell is so like that of Monodonta laevigata^ Sow. 



