64 
spur -like process ; but seems to differ from the preceding species, 
both in the length of its spire and of its spur. The number of turns 
in its spire shows that it is not a young shell of the preceding species, 
but that it is rather a perfect shell of a distinct species. 
Lamarck describes only three species of this genus as found fossil in 
the neighbourhood of Paris : JR.macroptera, II. columbaria, R.Jissurella. 
XXX. Mur ex. An ovate or oblong univalve, with a channeled 
base and varicosely tumid ; rough, spinous, or fringed longitudinal 
and projecting sutures. 
By confining the murices to the shells thus characterized, shells 
are excluded, with which Bruguiere and Lamarck have formed the 
genera cerithium, fusus, pyrula, pleurotoma, and fasciolaria. In 
the murices, the canal, neither suddenly truncated nor abruptly 
turned back, the columella with no fold, and the left lip of the 
opening always more or less apparent, always determine the genus. 
Murex tripterus , of Brander, Born, and Lamarck, is found fre- 
quently fossil in Hampshire, and at Grignon, in France. Brander, 
Foss. Plate III. Fig. 79 and 80. Lamarck informs us that its recent 
analogue exists in the sea, in the neighbourhood of Batavia. 
M. Contabulatus, Lam. is doubtless a variety of the preceding 
species. M. tricarinatus, Lam. M. asper, Brand. Fossil, hunt. Fig. 
77, 78, is very remarkable for the spinous projections proceeding 
from its frondose ridges. 
The shell, Plate Y. Fig. 16, is rather a rare shell in the Essex cliff. 
It is fusiform. The turns of its spire, which are generally six, are 
thinly set with not very prominent rug®, which, with faint transverse 
striee, are also observable on the body of the shell ; the opening is 
smooth on each side, and the canal is rather patent. The rug®, con- 
tinued to the body of the shell, induce me to term this shell Murex 
rugosus. 
A fossil murex is much more frequently found in this cliff, which 
seems to agree exactly with M. corneas, Linn, as figured by Lister, 
