98 MOLLUSCA FROM THE GREAT OOLITE. 
in having a plain surface ; it comes nearer in shape to Volvaria, but that has a truncated 
or notched base, and crenated lip to the aperture, besides several plaits upon the columella.” 
It has been proposed to form a new genus of it, to be called Cylindrites, but the 
following species (4. acwtus) having a conical spire, connects it with dcte@on Noe. ‘Min. 
Con.’ 5, p. 77, 1825. 
Notwithstanding their general resemblance to Actzeon, we believe the species here 
described to be generically distinct from the typical forms of that genus, and have there- 
fore proposed to retain the name Cylindrites for them. 
The genus may be divided into two sections : 
A. Species with the spire elevated and acute. 
B. Species with the spire depressed and mammillated. 
The species belonging to the second section appears to pass into the Acteonellz of the 
cretaceous system. 
A. Species with the spire elevated and acute. 
CyLinDRiTEs acutus. Sow. sp. Pl. VIII, fig. 9, 9 a, 3b. 
Acton acutus, Sow. 1824. Min. Con., t. 455, fig. 2. 
— — Morris. 1843. Cat. Brit. Foss., p. 138. 
- _ D’ Orb, 1850. Prod. Paléont., p. 299. 
— _ Bronn. 1848. Index Palwont., p. 10. 
Lesté subcylindricd, spird conicd, apice acuto, anfractibus (4) planis seu subconvezis ; 
anfractu ultimo margine rotundato. 
Shell subcylindrical, spire conical, apex acute; whorls (4) flat or slightly convex; the 
last volution rounded at its upper margin. 
Locality. This shell occurs in much greater numbers than all the individuals of the 
other species put together ; it may, in fact, be considered as one of the most common 
univalves in the Great Oolite near Minchinhampton. 
It occurs in the Oolite at Ancliffe, Wiltshire, whence the original specimens were 
obtained, which are figured and described in the ‘ Mineral Conchology,’ and Mr. J. de C. 
Sowerby has kindly allowed us the use of the same for examination and comparison. 
CyninprirEs cusprpatus. Sow. sp. Pl. VIII, fig. 10, 10a. 
AcT£ON cusPIDATus, Sow. 1824. Min. Con., t. 455, fig. 1. 
— — Morris. 1843. Cat. Brit. Foss., p. 138. 
— — D Orb. 1850. Prod. Paléont., p. 299. 
— — Bronn. 1848. Index Palont., p. 10. 
TORNATELLA CUSPIDATA, Deslongchamps. Mém. Soc. Linn. de Normandie, vol. vii, 
p. 136, t. x, figs. 25, 26. 
_ _ Brown. Illust. Foss. Conch., p. 85, t. xliii, figs. 11, 12. 
