5. AKERA. (1) Muller. 
ORDER IV. 
A. Terrestrial ; shell interior ; almost all with 4 tentacula. 
4. Limax. (2) Lin. 
Body elongated ; a 
fleshy disk instead of a 
mantle, anterior and co- 
vering the pulmonary ca- 
vity only. Pl. 13, fig. 18. 
Pl. 15, fig, 13. 
2. Testacenra. (3) Lam. 
Mantle very small, pos- 
terior. Pl. 16, fig. 18. 
3. PARMACELLA. Cuv. 
Mantle membranous, 
with the edges flaccid. 
Pl. 14, fig. 9. PI. 16, fig. 
9. 
B. Terrestrial ; shell exterior ; almost all with 4 tentaculc. 
4. Vitrina. Drap. He- 
tico-Lmax. Ferus. (4) 
Body protected in front 
by a sort of cuirass, and 
behind by a thin shell 
which may be partly co- 
vered by the lobes of the 
collar or mantle. Pl. 14, 
fig. 12. 
(1) Their hermaphroditism, the position of their two sexes, the complication 
and armour of their stomach, the purple liquor produced by several of their spe- 
cies, approach them to the Aplysia. 
(2) Their mouth has only an upper jaw, in the form of a dentated crescent, 
(61 ) 
Tentacula so short 
and broad as to appear 
wanting or replaced 
by a fleshy rectangular 
shield. Pl. 16, fig. 1, 2, 
ee nse 
GENERA. 
Orifice of respiration 
on the right side towards 
the front. 
Orifice of respiration 
posterior. = 
Orifice of respiration 
under the right side of 
the middle part of the 
mantle. 
Body too large to en- 
ter entirely within the 
shell. 
which enables them to gnaw herbs and fruits. 
(3) The 7, haliotidea lives under ground, and feeds principally on worms. M 
de Ferussac has observed, that its mantle expands extraordinarily when it is oS 
too dry a place, affording it a sort of shelter. 
(4) The mantle has a double edge ; the upper, which is divided int 
lobes, can extend far beyond the shell, and fold back to rub aul polish it. rae ge 
PULMONACEZ. 
