158 CONTRIBUTIONS 
tioned by M. Deshayes in the Tertiary of Europe—twenty- 
four of these in the Paris basin. Two species only, I be- 
lieve, have been heretofore observed in this country. 
From the Tertiary of Maryland, Mr Conrad has described 
the acuticosta. From the Upper Tertiary (Conrad) of Vir- 
ginia, the Miocene of Lyell, Mr C. has described the um- 
brifer. It would therefore appear that three species only 
of Murex in a fossil state are now known here, while 
eighty-nine are known to exist in the Tertiary of Europe. 
FAMILY ALATA. 
GENUS ROSTELLARIA. Lamarck. 
R. Lamarckii.* Plate 5. Fig. 164. 
Description. Shell fusiform, covered with longitudinal 
flexed ribs cut by numerous transverse striee, which in the 
adult are hidden, the whole surface being coated by a de- 
posit ; substance of the shell thick; spire elevated, acute 
at the apex; suture impressed, when coated as in the 
adult scarcely perceptible ; whorls about twelve, convex 
in the young, scarcely perceptible through the coating of 
the adult; canal at the base short, above nearly erect, 
extending half way up the spire, where passing in a curve 
* In naming this species in honour of the first conchologist of the age, 
1 do homage to that acumen of science which now penetrates to the 
study of the naturalist in every quarter of the globe. 
