306 Rev. M. J. Berkeley’s Anatomy of 
different vessels which expose the blood to the action of the air, are 
spread, is so extremely transparent that a clear view is obtained of the 
contents of the cavity without making any incision; it has (at least 
in specimens preserved in spirits) a slight degree of rigidity and elasticity, 
like the shell which protects it; and perhaps this circumstance 
compensates in some measure for its extreme thinness. So much is this 
the case, that even when the shell is removed, it is able in general to 
support itself without falling down like the flaccid membrane of Pulmo- 
nifera in general, 
The mass of the mouth is oval, and has the upper lip furnished with 
a horny crescent-shaped plate, which has a single projecting tooth in the 
center as in Limax, and not numerous toothlets as in Helix. 
The mass itself has a flat forked muscular strap shaped like the letter 
Y, attached to it behind, embracing its under-side firmly with the two 
arms, which shortly after become confluent, and the single strap formed 
by this confluence is inserted into the foot behind. By means of this 
muscle the mass is retracted, together with a portion of the skin imme- 
diately surrounding the mouth itself. Above the muscle between its 
arms, the cartilaginous cone of the tongue makes a slight projection. 
The tongue itself which lines the bottom of the cavity of the mass, or 
rather of an organ fixed to it, which performs the function of a lower 
lip, is most beautifully and regularly chequered in parallel, transverse 
and longitudinal lines, formed by most minute subtriangular plates or 
spiculez, whose points are directed backwards exactly as in Helix 
( aspersa, ) 
Immediately above the cone is the commencement of the cesophagus ; 
on each side of which the salivary ducts enter into the mass; and above 
these the upper ganglions of the nervous cord, for the mass is evidently 
formed of two confluent ganglions; each gives off a nerve to the large 
tentaculum on its own side; and above a nerve forked soon after its origin 
proceeding to the upper part of the mass of the mouth. The lower 
ganglion, connected on each side by a cord with the central ganglions is 
large and nearly circular, giving off nerves on all sides, as in Helix. The 
cesophagus, as usual, passes through the circle formed by the junction. 
The cesophagus is soon confounded with the stomach which is a 
membraneous dilatation, consisting of two parts, The salivary glands 
