42 The Shell-Collector’s Handbook. 
7. Physa, Lam.—Shell spiral, thin, polished ; 
spire sinistral; non-operculated. Animal with two 
long tentacles, with the eyes at their base; mantle 
very large so as to cover part of the shell. 
8. Limnea, Brug.—Shell oval, thin, translucent ; 
mouth oblong; columella with an oblique plait; non- 
operculated. Animal with two short triangular 
tentacles bearing the eyes at their base ; foot oval. 
9. Ancylus, Geoffrey.—Shell conical, oblong, 
limpet-shaped ; apex pointed and bent to the right; 
spire dextral or sinistral. Animal with two cylindrical 
tentacles, with the eyes at their base ;. foot large. 
(TERRESTRIAL.) 
Famity II.—Limacide. 
Shell placed under the mantle, rudimentary or 
shield-like. Body united in its whole length with the 
foot beneath, there being no ‘ visceral hump’; ten- 
tacles four, cylindrical, the dorsal pair bearing the 
eyes ; mantle shieldlike. 
10. Arion, Ferussac.—Shell consisting of loose 
calcareous granules. Mantle shagreened, not striated 
concentrically ; respiratory orifice placed on anterior 
half of the mantle ; tail provided with a slime gland. 
11. Geomalcus, Allman.—Shellsolid, unguiform, 
concentrically striated. Body capable of great ex- 
tension; mantle finely shagreened ; tentacles short, 
eyeless ; respiratory orifice placed more anteriorily 
than in Limax; tail provided with a large slime 
gland. 
12. Limax, Linn.—Shell oval or unguiform. 
