62 TRACHELIPODA. HELIX. 
the pillar lip, and the outer lip thin. Example, A. 
Dombeyana. 
The auricule are land shells, and are found in the warmer countries of the 
globe. The species are very limited in number. 
Fossil species are rare, and are met with in the newer formations. 
SUB-DIVISION II, — Animals provided with two tentacula. 
Genus LXXXI.— BULINUS. — Bruguiere. 
Generic Character.— Shell oval or oblong, generally 
thin, and covered with a slender epidermis; spire obtuse, 
variable in length and number of its volutions, which for the 
most part are few ; aperture oval, wide, anteriorly rounded ; 
outer lip simple, reflected, continuous, and joining the colu- 
mellar lip without an emargination, and reflected over part 
of the body ; columella smooth, straight, without a trunca- 
ture, or widening at the base. 
Bulinus costellatus. Plate LV. fig. 12. B. cylindracea. 
Plate V. fig. 5. The former is from the fresh water forma- 
tion, Isle of Wight. 
The Bulini are distinguished from the Achatine by being destitute of the 
notch at the junction of the outer and pillar lips. They are land shells, the 
species are numerous, and inhabit almost all countries. 
Fossil species are only met with in the fresh water formations. 
Genus LXXXII. — AGATHINA, — Deshayes. 
Generic Character.— Shell oblong-ovate ; smooth and 
polished, body and spire nearly of equal length; volutions 
inflated, and terminating in an acute apex ; aperture oblong, 
narrow, contracted above, and truncated below ; outer lip 
acute, but never reflected. 
Agathina pellucida. Plate V. fig. 22. Found in the 
Calcaire-grossier at Paris. 
Known only in a fossil state. 
Genus LX XXIII. — HELIX. — Linneus. 
Generic Character. — Shell orbicular, thin, subglobose ; 
body very large, spire short, and small in proportion to the 
body ; aperture oblique ; outer lip reflected, and interrupted 
by the bulging of the body ; columella confluent with the 
outer lip, and situate on the lower portion of the axis. 
Destitute of an operculum. 
Helix turtonensis. Plate IV. fig. V. Found in the Cal- 
caire-grossier. 
The Helices are land shells, and have been met with in almost all portions 
