1Q15.] E. GuosH: The Anatomy of a Burmese Slug. 157 
surface of the radula is applied on these surfaces. A little in 
front of the posterior blind end of the cavity, the lower and 
outer walls of the sac is lined by a single layer of large granular 
cells with round or oval nuclei. This layer is continuous with the 
cubical epithelium of the radula. At the extreme posterior end 
of the cavity of the sac lies a mass of cells arranged obliquely 
and probably in several rows. These are placed on a thin layer 
of connective tissue, and seem to be continuous in front with 
the layer of granular cells just mentioned, while the connective 
tissue layer is continued in front to that of the radula. 
The corneous layer on which the teeth are placed becomes 
suddenly narrowed down, just behind the point where the cubi- 
cal epithelium ends, and is continued backwards as a thin layer 
to the tip of the cavity where it ends above the upper tiers 
of cell of the cellular mass just mentioned. The dorsal and 
inner lining of the cavity is convex and have the teeth 
of the radula embedded in them. The cavity of the sac is 
thus so narrow as to keep the radula between its two surfaces, 
there being no space left between the radula and the lining 
of the cavity of the sac. The postero-dorsal wall of the sac 
is thick and projects into the cavity of the sac. The base 
of the projecting mass consists of a curved stratum of connective 
tissue in front of which lies an oval mass of large muscular fibres, 
arranged transversely and separated widely from each other by con- 
nective tissue fibres and cells. Still in front lies an elongated mass 
of connective tissue cells embedded in a gelatinous matrix tra- 
versed by a few fine fibres, on the lower aspect of this wall lies a 
row of much elongated obliquely-placed cells, continuous round 
the blind end of the cavity to the cellular mass on the upper 
and outer aspect of the cavity. On the lower surface of this 
cellular layer are seen two or three transverse rows of teeth 
one before another and placed flatly on the homogeneous layer. 
In front of these rows, the teeth are arranged obliquely on 
the thick homogeneous layer between rows of cells continued 
to the posterior and inner wall of the sac, and filling up the 
space between the successive rows and probably between the 
individual teeth of the same row. ‘The cells are probably con- 
cerned in the secretion of the teeth of the radula. 
(iii) The two salivary glands are fused to form a single 
oval mass, but there are two salivary ducts which pass to their 
destination as usual. 
(iv) The oesophagus ends in the substance of the liver. Its 
course is exactly similar to that in other species. 
(v) The digestive gland is elongately conical in shape and 
rounded in front. It ends about 1°5 cm. in front of the 
posterior end of the mantle. The upper surface is convex from 
side to side; it presents the S-shaped curve of the rectum in 
its anterior portion about th the length of the gland from this 
end. The cavity of the liver is a C-shaped slit in transverse 
section. 
