428 Rev. M. J. Berkeley on Voluta denticulata. 
I was surprised to find manifest indications that both were pulmonife- 
rous, which were confirmed on a minute inspection of the internal 
structure, as far as perhaps could be expected in such small animals. I 
was enabled in the former to trace distinctly the course of the vessels, and 
was decidedly of opinion that the lungs were constructed for the breath- 
ing of air unmixed with water. In the other case I was not so successful, 
though the utmost pains were taken: but as the animal is only half the 
size the difficulty was much increased. JI am enabled however to assert 
that I could detect nothing like branchie; and, what is more to the 
point, that the vault of the cavity of respiration was traversed by a mul- 
titude of minute vessels all tending one way towards a large vessel running 
down in the direction of the heart; which is exactly the structure in 
_ pulmoniferous Mollusca. This perhaps will be esteemed as decisive 
_when the external characters of the animal are taken into consideration. 
VoLUTA DENTICULATA, Mont. 
Foot obovate-oblong, pale ochraceous with shades of cinereous, obtuse 
in front, more or less obtuse behind, not evidently composed of two 
lamin. 
Tentacula highly contractile, filiform, obtuse, cinereous, slightly 
annulated, darker at the tip; eyes at the internal base. 
Muzzle porrected, not truly proboscidiform, lip large, notched in 
front asin Limnea, cinereous: the central portion faintly annulated ; 
on each side near the margin there is a round raised spot. Mouth fur- 
nished with a small tooth above. 
Mantle closed all round, with the exception of a perforation at the 
point of juncture of the outer lip and spire for the admission of air. 
Feces cylindrical (as in Limnea). 
Operculum none. 
If the mantle be carefully opened, and the vault of the cavity of 
respiration examined with a lens under water, the pulmonary veins are 
seen very distinctly running from all sides into one large vein, which runs 
close to the sac of viscosity and carries the blood directly into the heart. 
The sac of viscosity is very large, and without minute inspection might 
be taken for branchie : a comparison with that organ in Lymn@ide veri- 
