Casey — Notes on the Pleurotomidae. 151 
Orthosurcula hn. gen. 
Before proceeding to define some of the more typical allies 
of Surcula, it will be of advantage to refer toa generic type as 
named above, combining some of the features of the preced- 
ing group and the true Surculids. The species are large, 
moderately stout, completely devoid of ribbing and have the 
beak elongate, tapering, relatively slender and straight. The 
spirals are close-set, moderate or small in size, sometimes 
granulose, and the whorls are more or less broadly inflated 
below and feebly concave posteriorly. The outer lip projects 
in the middle as a broad rounded lobe beyond the juxta- 
sutural part, with the sinus large and posterior, as in Surcula, 
and the embryo is paucispiral. The types are the upper Eocene 
Pl. longiforma Ald., of Red Bluff, Miss., and the European 
Eocene Surcula transversaria Lamk. These species have 
much finer sculpture than the living Surcula australis Lamk., 
which is also an Orthosurcula. 
Sureula H. et A. Adams. 
Turricula Schum. (nom. praeocc.). 
This genus is composed of a moderate number of more or 
less large species, stout in form, with the beak somewhat elon- 
gate and the columella distinctly twisted, the beak generally 
having a distinct oblique external ridge which is wholly want- 
ing in Orthosurcula. The surface has numerous short oblique 
costae, confined throughout to the peripheral ridge, and, in a 
few species suchas tornata only visible on the nepionic whorls, 
becoming lost on the larger whorls — like the peripheral dentic- 
ulation of some forms of Gemmula. The embryo is small 
and paucispiral. The median parts of the outer lip project 
beyond the juxta-sutural part in a broad rounded lobe and 
the sinus is large, rounded and posterior, in these respects 
resembling Bathytoma and Megasurcula. The type is SN. 
javana Linn. (=nodifera Lamk.), from the coast of China, 
and the genus will include as well ¢uberculata Gray, tornata 
