PLEUROTOMID®. 159 
narrow, terminating in a rather short, truncated canal; lip-sinus 
near the suture. No operculum. 
Foot dilated in front, and attenuated behind; eyes placed on 
peduncles connate with the tentacles, and at about the middle of 
the latter, and exterior. Teeth hastiform (1-0-1). 
The animal of Mangilia is slow in its movements. It can 
sustain itself at the surface of the water, shell downwards. The 
oviposit consists of membranous hemispherical capsules, having 
a central opening, ordinarily attached to the interior of old 
bivalve shells. Each capsule contains from 200 to 300 eggs 
(Jeffreys, Brit. Conch., iv). 
The great number of small species, inhabiting all portions of 
the globe, which have been referred to Mangilia, may be conve- 
niently divided into the following sections :— 
Section MAnGILtIa (restricted). Shell longitudinally costulate ; 
aperture narrow; lip varicose; sinus well marked; canal short. 
Section CyrHara, Schum., 1817 (not Klein, 1753 — Harpa. 
Otocheilus, Conr.; Cytharella, Monteros; Eucithara, Fischer, 
1883). Shell Columbelliform, longitudinally costellated ; spire 
short; aperture narrow; outer lip denticulated within; colu- 
mellar lip striated. 
Section CyrHaropsis, A. Adams, 1865 (not Citharopsis, Pease 
= Columbellide). Whorls of the spire cancellated ; columella 
sillonated ; canal curved, elongated. 
Section GiyrHostoma, Gabb, 1872. Shell fusiform; columellar 
lip plicated throughout ; outer lip thickened, plicate within ; sinus 
profound ; canal long, somewhat bent. 
Founded on a West Indian tertiary fossil, but some living 
species are referred to the group. 
Genus CLATHURELLA, Carpenter, 1857 (Defrancia, Millet, 
1826.) 
Apex mammillary ; sinus varicose, sutural; columella tubercu- 
lated posteriorly, rugose in front; canal slightly curved. Den- 
tition, Pl. 33, figs. 56,57. Defrancia was preoccupied by Bronn 
fora genus of Polyzoa; but that is said to be a synonym of 
Pelagia, Lamouroux; so that perhaps it ought to be restored for 
the mollusks. Clathurella appears to differ from Mangilia prin- 
cipally in its more rounded whorls, and cancellated sculpture. 
