202 DOLIID^. 



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. C. striata^ Lam. (Ixii, 30). Also Tertiary and Cre- 

 taceous. 



Oniscia, Sowb. 



Etyni. — Oniscus, a wood-louse. 



Syn. — Morum, Bolten. Ersina, Gray. Lambidium, Link. 



Distr. — 9 sp. West Indies, China, Galapagos. Fossil, 3 sp, 

 Miocene ; United States, St. Domingo. 0. oniscus, Lam. (Ixii, 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. 0. cancellata^ Sowb. (Ixii, 32). 



Pachybatron, Gaskoin. 



Distr. — 3 sp. Ti'opical ; West Indies, East Indies. P. Mar- 

 ginelloideum, Gask. (Ixii, 33). 



Shell small, subcylindrical, 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. 



Family DOLIID^. 



Shell thin, with short spire and very large body-whorl, covered 

 Avith 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). 



DoLiUM, Linn. 



Tun-shell. Syn. — Perdix, Montf. Doliopsis, Conrad. 



Distr. — 15 sp. Mediterranean, West Indres, off Rhode Island, 

 Ceylon, China, Philippines, Australia. Fossil, 8 sp. Cretaceous, 

 Tertiary ; So. Europe, United States. D. perdix, Linn. (Ixii, 

 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 ; Ixii, 36 ) is founded 

 upon the lai'va of Dolivim ; it has four tentacles, and the foot is 



