482 MOLLUSCA SUB-KINGDOM VI 
is characterised by a line running parallel with the suture, and creating a narrow 
suture band. 
Family 3. Pleurotomidae. Stoliczka. 
Shell fusiform, with moderately high spire. Aperture elongated, produced anteriorly 
in a longer or shorter canal. Outer lip with a slit or notch below the suture. Operculum 
horny, sometimes absent. Cretaceous to Recent. 
Upwards of 700 recent and 1000 fossil species have been described, of which 28 
are Cretaceous. 
Plewrotoma, Lam. (Figs. 995-998). Shell turriculated, spire long. Body whorl of 
nearly equal length with the spire; canal long and straight; columellar margin 
A B C 

Fic. 995. Fic. 996. 
A, Plewrotoma notata, Broechi var. (=P. monilis, A, Pleurotoma (Genota) ramosa, 
Hoernes). Miocene; Baden, near Vienna. 6, P. (Surcula) Bast. Miocene; Grund, Hungary. 
Lamarcki, Bell. Miocene; Baden, near Vienna. C, P. B, P. (Cryptoconus) filosa, Lam. 
(Surcula) belgica, Nyst. Oligocene; Weinheim, near Caleaire Grossier; Grignon, near 
Alzey. Paris. 
smooth. Outer margin of the aperture with a narrow, deep sinus, situated at or some 
distance below the suture. 
Operculum pointed ovate, 
with apical nucleus. Cre- 
taceous to Recent. 
Sub-genera: Surecula 
(Figs. 995, B, C); Genota, 
Adams (Fig. 996, A); Doli- 
chotoma (Fig. 997), Oligo- 
toma, Rouwaltia, Bellardi ; 
Cryptoconus, v. Koenen 
(Fig. 996, B); Drillia (Fig. 
998), Bela, Gray ; Lachesis, 
Risso, ete. 
Clavatula, Lam. (Fig. 
999). Differs from Plewro- 
toma in that the outer 

Fic. 997. Fig. 998. » z } | ll 
aro 7". r hs , 
Pleurotoma (Dolicho- Pleurotoma (Drillia) et et 1s cut oY a shallow 
toma) cataphracta, incrassata, Duj. Mio- Clavatula asperulata, triangula r notch, and 
Brocchi. Miocene ; cene; Steinabrunn, Lam. Miocene; Grund, leus f arcu] sty. 
Baden, near Vienna. near Vienna. 2/3. Hungary. nucleus Of opercuiumM 
situated in the middle of 
the anterior margin. Cretaceous to Recent. Sub-genera: Pseudotoma, Clinura, 
Bellardi. 
