( 65 ) 
C. Aquatic ; 2 tentacula. 
Without a shell. 
5. Oncuipwm. (1) Bu- 
chanan. 
A broad fleshy mantle. 2 Long retractileten- Orifice of respiration 
Pl, 16, fig. 8. tacula, and two triangu- under the posterior part 
lar lips. of the mantle. 
With shells. 
6. Ancytus. Geoff: 
Eyes at the inner base 
of the tentacula. 
bo | 
. Pranonsis. (2) Brug. 
Pl. 16, fig. 10. 
—~Tentacula thin, fili- Ditto. 
form. 
Ne 
. Lymnaus. (3) Lam. 
Tentacula compress- _ Eyes near the base of 
ed, broad, triangular. the inner edge. 
8. Puysa. (4) Drap. 
Two dentated lobes to Tentacula thin, point- —_ Eyes at the inner base, 
the mantle. ed. which is much enlarged. 
9. Auricuta. Lam. 
40. Conovura. Lam. 
41. Tornarenna. Lam. Animals unknown, but (from the form of the shell 
and the absence of the operculum) approximating 
to the Auricula, 
42. Pyramipriia. Lam. ane 
4€ 
(1) The mollusea, destitute of jaws, have a muscular gizzard, followed by two 
membranous stomachs. 
(2) A red and abundant liquor exudes from the edges of its mantle, but it is not 
their blood ; they are the constant companions of the Lymnzi in all stagnant waters. 
(3) We find them floating on the surface of the water with the foot turned up- 
wards, and very rarely creeping on hard substances ; when disturbed they fall or 
sink, and remain a long time immoveable before they reappear at the surface. 
(4) This animal, when it swims or creeps, covers its shell with the two dentated 
lobes of its mantle. 
