152 Trans. Acad. Sci. of St. Louis. 
Dillw. (=javana Kiener non Linn.) and fulminata Kiener, 
from the Indo-Pacific fauna, and the South African Clavatula 
gravis of Hinds. Surcula, as far as known to me, is a mod- 
ern development and most of the very numerous old Tertiary 
forms will constitute other genera. 
Pleurofusia De Greg. 
This name was given by De Gregorio to a species which he 
described and figured under the name longirostropsis, stating 
that it may bea variety of servata Con., and indicating the lat- 
ter species as one of the generic types. Nothing very similar is 
known to me from the Upper Claiborne ferruginous sand, but 
there is a specimen in the cabinet of Mr. Aldrich, from the 
Lower Claiborne, which greatly resembles the figure referred 
to. At any rate, it seems evident that Pleurofusia, as repre- 
sented by servata and the specimen alluded to, must be rec- 
_ ognized as valid. The species are moderate to rather small 
in size and of somewhat slender form, with rather slender, 
somewhat elongate beak and strong, longitudinally and trans- 
versely rounded, almost entire costae, generally some seven or 
eight in number. The embryo is conoidal and multispiral to 
obtuse and paucispiral in form, but never has any conspicuous 
longitudinal riblets. The fasciolar surface is usually well de- 
fined, in great part obliterating the ribs below the suture, but 
in some cases is less evident, the ribs being strong thoughout 
the length of the whorl. The species chiefly characterize the 
upper Eocene and Vicksburg Oligocene of the Southern States, 
but would seem to have originated in such forms as langdoni 
Ald., of the lower Eocene, which has more numerous ribs, 
and extend upward at least to the lower Miocene of West 
Florida, where the genus is represented by a species resem- 
bling servata. The other species known to me are declivis 
Con. and oblivia, vicksburgensis, evanescens, collaris and hil- 
gardi Csy., with several others still undescribed. Such species 
as servatoidea Ald., will form an allied genus somewhat resem- 
bling Pleurofusia in the ribbing but differing in the position 
of the anal sinus and character of the sculpture. 
