LAWSON, ON LIMAX MAXIMUS. 15 
filled with transparent fluid, and contains, floating in this 
latter, many well-marked circular endoplasts, with nuclei 
in their interiors, and has attached to its inner edge a deli- 
cate twig from the excretory duct (Pl. II, fig. 3). 
The gullet is a canal, at first narrow as it leaves the mouth, 
but having passed the nervous collar it widens so as to re- 
semble a funnel, and its walls become more dense and mus- 
cular ; it is usually of a dark-brown colour, this being for the 
most part owing to a quantity of bile, which it nearly always 
contains, and which renders it not unlikely that much of the 
true digestive process is gone through here. Like the other 
division of the alimentary canal, the cesophagus exhibits the 
tendency to curve spirally in its passage from head to 
stomach, and though prior to its passage through the second 
nervous circle it is horizontally situate in the median line, 
yet, between this and the stomachal sac, it turns to the left 
and downwards, and again bending to the right in the central 
axis and, equidistant from the head and caudal extreme of 
body, it terminates in the stomach. It is related above to 
the heart, pericardial gland, lung-sac, nervous masses, ante- 
rior lobe of liver, and large and small intestines, the rectum 
just passing over it between the head and ganglionic centre ; 
it rests upon the foot (having the pedal gland below it) and 
inferior nervous masses ; is bounded on the right by the ante- 
rior portion of the reproductive organs, on the left by a fold 
of the large intestine, and on both sides by the tentacula 
and their muscular apparatus. It is little more than two 
inches in length, has a calibre of + inch at the cardiac orifice 
of the stomach, and measures diametrically inch as it 
leaves the mouth. Histologically, the cesophagus is identical 
with the other divisions of the alimentary canal except the 
stomach, and therefore the sketch of its microscopic anatomy 
will suffice for all, except the latter. Two coats enter into 
its composition, a fibro-muscular and pseudo-mucous, neither 
of which, however, can be detached without injury to the 
other. The first, most external, or visceral layer, when ex- 
amined under a low power, presents to the eye a collection of 
muscular and connective tissue fibres, nerves, and blood- 
vessels, mingled heterogeneously together; but if the larger 
branches of the latter be carefully teased out, and a small 
section submitted to a much higher power, it is then seen 
that the outer coating is composed of two distinct strata of 
nucleated, non-striated, muscular fibres, crossing each other 
pretty nearly at right angles, and, blending with them 
and pursuing an undulatory course, a few fibres of the 
elastic connective tissue (fig. 4). The muscular fibres are 
absent in some localities, thus leaving small rectangular 
