202 DOLIIDA. 
slightly reflected; inner lip regularly plicate, the anterior pli- 
cations the largest; outer lip rather thick, subreflected, plicate 
within. Animal and operculum unknown. A single recent 
species. (. striata, Lam. (1xii, 30). Also Tertiary and Cre- 
taceous. 
Oniscra, Sowb. 
Htym.— Oniscus, a wood-louse. 
Syn.—Morum, Bolten. Ersina, Gray. Lambidium, Link. 
Disir.—9 sp. West Indies, China, Galapagos. Fossil, 3 sp. 
Miocene; United States, St. Domingo. O. oniscus, Lam. (1xii, 31). 
Shell subcylindrical, conoidal, with short spire, and canal 
reflected at the base, surface tuberculated, mouth linear, right lip 
reflected, thickened and plicate within, inner lip plicate. 
These little shells are known by their transversely ribbed 
nodulous whorls, and prominent, recurved siphonal canal; when 
fresh the surface is covered with a fine velvety epidermis. 
ONISCIDIA, Swains. Oval, tuberculate-cancellate, inner lip 
granulated. O. cancellata, Sowb. (1xii, 32). 
PACHYBATRON, Gaskoin. 
Distr.—3 sp. Tropical; West Indies, East Indies. P. Mar- 
ginelloideum, Gask. (xii, 33). 7 
Shell small, subeylindrical, longitudinally striated ; spire very 
short, but with sharp apex; aperture narrow, very long, the 
inner lip spread over the body-whorl and transversely plicate, 
the outer lip thickened and denticulated within. 
Famity DOLIIDA. 
Shell thin, with short spire and very large body-whorl, covered 
with revolving ribs. 
Animal very large, with a wide head bearing two elongated, 
obtuse, distant tentacles, dilated at the base, where are situated 
the eyes, proboscis cylindrical, greatly developed, extensible 
and flexible, foot oval, very large, lobed and dilated in front, 
with a horizontal groove. No operculum in the adult. Denti- 
tion (xi, 32). : 
Douium, Linn. 
Tun-shell. Syn.—Perdix, Montf. Doliopsis, Conrad. 
Distr.—15 sp. Mediterranean, West Indies, off Rhode Island, 
Ceylon, China, Philippines, Australia. Fossil,8sp. Cretaceous, 
Tertiary; So. Europe, United States. D. perdix, Linn. (1xii, 
21, 34). 
Shell thin, ventricose, inflated, subglobular, with revolving ribs; 
mouth very large, the outer lip crenulated, columella canalicu- 
lated. The genus Macgillivraya (xx, 44,46; lxii, 86) is founded 
upon the larva of Dolium; it has four tentacles, and the foot is 
