PLEUROTOMIDA. 183 
Shell fusiform or turriculated, oblong-oval, smooth ; aperture 
ovalelongated, large, produced into a twisted canal in front ; 
columella carinated, anteriorly twisted, with a small basal 
plication. 
Famity PLEUROTOMID. 
Shell fusiform, canaliculated, outer margin of aperture with a 
slit near the suture. Operculum corneous, annular, not always 
present. Animal with tentacles wide apart, the eyes at their 
outer bases. 
PLEevRotToMA, Lam. 
Etym.—Pleura, the side, and toma, a notch. 
Syn.—Turris, Humph. Cochlespira,Conrad. Gemmula, Weink. 
Eucheilodon, Gabb. 
Distr.—Over 500 sp. World-wide; low-water to 100 fms. 
Fossil, nearly as many. Cret.—. P. babylonia, Lam. (lvii, 13). 
Shell turriculated, fusiform, terminated anteriorly bya straight, 
more or less long canal; aperture oval, columellar lip smooth, 
straight or sinuous ; outer lip somewhat sinuous, with a posterior 
sinus. 
surcuLA, H.and A. Adams. Turriculated, internal lip obsolete ; 
canal long, narrow, slightly twisted. P. nodifera, Lam. (lvii, 14). 
SURCULITES, Conrad. Shell with spire and body-volution nearly 
equal; the latter obconical, rectangular near the top, and flattened 
or concave above from the angle to the suture ; sinus of lip above 
the angle of the whorls, shallow and broad. §S. annosa, Conrad. 
Mr. Conrad never characterized it; but his type-species has the 
characters given above. It seems to be very near to Surcula but 
may probably be retained for a group of Tertiary species, with. 
obeconic body-volutions, usually referred to Pleurotoma, and 
forming a kind of transition toward the Conidz (Meek). 
GENoTA, H. and A. Adams. (Pseudotoma, Bellardi. Crypto- 
conus, Koen. Dolichotoma, Bellardi. Roualtia, Bell.?) Shell 
mitriform ; whorls finely cancellated ; aperture elongated, canal 
short; sinus profound. P. Mitreformis, Kiener (lvii, 15). 
BRACHYTOMA, Swains. Shell strombiform; columellar lip rather 
thick; outer lip ascending and forming a sinus or narrow canal 
near the suture. P. Stromboides, Sowb. (vii, 16). 
CONOPLEURA, Hinds. Shell coniform; aperture narrow, sinuous; 
columellar lip callous ; canal very short; outer lip sinuous, with 
a profound lateral sinus. P. striata, Hinds (lvii, 17). 
DRILLIA, Gray. (Moniliopsis, Conrad.) Turriculated ; aper- 
ture oval, oblique; canal short, twisted; columellar lip strongly 
callous above. Animal with approximate tentacles and eyes at 
their extremity. P. gibbosa, Kiener (lvii, 18). 
CRASSISPIRA, Swains. Shell somewhat claviform, tuberculated ; 
