TOK. ] E. GHosu: The Anatomy of a Slug. 193 
in the present species. There is no left Simrothian gland in 
A. sarasinti (4). 
Minute structure.—First portion (pl. xxvi, fig. 24).--The wall 
consists of the following layers from without inwards :— 
(rt) Athin layer of connective tissue forming a sheath 
round the tube. 
(2) A layer of large granular cells more or less cylindrical 
in shape and with large nuclei placed on one side ; 
they are arranged radially and obliquely, being 
attached to the first layer at their outer ends and 
to the next by the inner. In a transverse section 
one finds several oblique sections of the cells. 
These seem to be muscle-cells. 
(3) A layer of muscle-fibres arranged longitudinally. 
(4) A layer of transversely arranged muscle. fibres. 
(5) A layer of submucous tissue. It forms numerous 
folds projecting into the lumen. Small muscle- 
fibres can be traced into it from the fourth layer. 
(6) The mucous membrane consists of a single layer of 
columnar epithelium. 
Second portion (pl. xxvii, fig. 26).—The different layers are :— 
(1) An outermost layer of connective tissue. 
(2) A thick transverse layer of muscular fibres inter- 
mingled with white and yellow fibres. 
(3) A single layer of cubical cells with round tiuclei. The 
epithelium is not folded. 
Two or more loops of this portion of the tube may be held 
together in connective tissue. 
Third portion (pl. xxvii, fig. 25).—The various layers are :— 
(1) A layer of thick longitudinal muscle-fibres—the indivi- 
dual fibres are separated by connective tissue. 
(2) A thin transverse layer of muscle-fibres; some of 
these are continued into the folds of submucous 
tissue. 
(3) A submucous coat of loose connective tissue thrown 
into ten or twelve folds. 
(4) The mucous membrane consists of a single layer of 
columnar cells with oval nuclei. 
(6) The external aperture of the male genital organ seems 
to be situated on the inner side of a triangular process between 
it and the base of.the right lower tentacle. 
(II) FEMALE GENITAL ORGANS (pl. xxvi, figs. 17, 18). 
(1) The hermaphrodite gland is a large lobulated body 
lying closely apposed to the posterior end of the albumen gland. 
The dorsal surface is marked with a longitudinal groove for the 
