GASTEROPODA. TRITONIAD. 295 
Back slightly convex, of a grey colour, sculptured into un- 
equal irregularly rounded tubercles; the sides smooth, the 
right with two tubercles, one before, the other behind the mid- 
dle; both are pierced, to serve the purposes mentioned in the 
character of the family. Length from one to two and half 
inches. 
This very rare species has been taken in deep water, off 
Falmouth, three or four times only, by Mr. J. Cranch. 
The animal figured has unfortunately lost its respiratory 
organs, which is the case with all my specimens; but as it has 
never been given before as a British production, I thought that 
I ought not to withhold the valuable fragment that remains, 
since it exhibits all the specific characters. 
As this part of the synopsis was on the point of being 
printed, I received from Mrs. Griffiths, who found them at 
Torquay, three very fine specimens of this animal, the largest 
of which was three inches in length and two in breadth; and I 
very much regret that my time will not permit me to enter into 
a full detail of its internal structure. 
The mouth is composed of a muscular mass, and is furnished 
with two hard horny jaws, and a spiral tongue. 
The central mass of the nervous system consists of four gan- 
glia, placed close to each other, and are brought into commu- 
nication with two other (sympathetic) ganglia by branches from 
the nervous collar. 
The cesophagus is long and thin, longitudinally elevated in- 
ternally. The salivary glands are granulose; one is placed on 
each side of the cesophagus. The stomach is membranaceous, 
very slightly dilated, and is partially embraced by the liver, 
which is very small. The rectum is elevated internally like 
the cesophagus. 
Genus 9. IpuLiA. 
Corpus posticé acuminatum. Branchie decem, peduncu- 
late. Tentacula simplicia. 
Body acuminated behind. Branchiz ten, pedunculated. 
Tentacula simple. 
