296 Shells of the Genus Conus in the Lias. 
I am indebted to the liberality of M. Deslongchamps for 
the principal drawings. 
Conus cadonensis. Shell smooth, slender, with six or seven 
volutions and an acuminated spire, posterior edge of each vo- 
lution carinated, and slightly crenulated. Posterior part of 
each volution rather concave, and very finely longitudinally 
striated. 
Fig. 1. 
Fig. 1. a. represents an internal cast of a variety with a shorter spire. 
This cast is still imbedded in the limestone in which it was found. It 
is regarded as a mere variety of 5, because it is well known that in this 
genus the height of the spire differs greatly in the same species, as for 
example, in Conus antediluvianus, to which C. cadonensis approaches 
most nearly. 
Fig. 1. b. A perfect specimen of Conus cadonensis, in the possession of 
M. Tesson, in which the entire shell is extant. 
Fig. 1. c. A magnified representation of a part of the crenulated poste- 
rior edge of one volution of C. cadonensis. 
Conus concavus. Shell smooth, conical, contracted near the 
middle, with a concave depressed spire, consisting of nine 
volutions, each volution carinated at the external edge, and 
very slightly longitudinally striated. 
Fig. 2. 
Fig. 2. a. A perfect specimen of Conus concavus in the possession of M. 
Tesson, from a drawing by M. Deslongchamps. In this specimen the 
shell itself is extant. F 
Fig. 2. b. represents the concave spire of the same. ; 
Fig. 2. c. is a section of the spire, showing the depth of the concavity. 
Fig. 2. d. A magnified section of a portion of the same, showing the form 
of the volutions. | 
