CONOVULUS. 297 
respect to each other, and in the method, as the collective 
value of the characteristic organs either of one or the other 
preponderates ; for imstance, the Cyclostoma elegans, a land 
branchifer, falls into natural position with the marine Pectini- 
branchiata. And though Carychium and Acme are Pulmoni- 
fera, and the Pyramidelliide Branchifera, still the peculiarity 
of their organs and shells associates them nearly as closely 
with the marme as with the terrestrial Mollusca. 
CONOVULUS, Lamarck. 
C. pENntIcuLATUS, Mont. et Auct. 
C. denticulatus, Brit. Moll. iv. p. 194, pl. 125. f. 3. 
Animal inhabiting a spiral shell of 64 volutions ; the first 
very large and ventricose, comprising #ths of the whole; the 
others are short, flat, and closely packed, with the apex as 
‘much reflexed as in many of the Chemnitzie; it is invested 
with a lightish brown epidermis, which often forms, at the 
upper part of the lower volutions, a row of minute, close-set, 
hairy papille, with a short filament proceeding from each ; 
these are very caducous. 
It is curious that the reflexed apex, or the fold within the 
aperture, invariably produces an animal with eyes immersed 
either at the centre of the bases, or more usually at the 
internal angles of the tentacula; for instance, this is seen in 
Conovulus, Pedipes and Carychium, Ternatella, Chemnitzia 
and Hulima and in the Limneade that have a certam con- 
nection with the Conovulide, as most of them have more or 
less developed folds on the columella, and show the same 
tendency to a basal position of the eyes. 
The mantle is even with the shell, thick, and fleshy; the 
neck is very long, often far protruded, and forms beyond the 
tentacula a very elongated muzzle, which expands into a large 
subcircular, arcuated, bilobed emarginate disk, with the buccal 
orifice in the centre quite beneath, and cloven vertically and 
crosially: this is the head, which is always in advance of the 
foot: there are no neck-lobes, but two very small suboval 
head-lappets may be observed near the terminus. The tenta- 
