imens which have been killed with great precaution. Tht shield
or mantle is oval and has an oval openii^, the pneumostoma, near
its right edge, considerably beyond the middle of the entire
length of the mantle. This opening leads to the lung, and near
it, ia the mantle cavity, lie the anus and the excretory opening



222 MORPHOLOGY OF INVERTEBRATE TYPES

or aephrostoma. The genital opening also is situated on the right
side, in front of the mantle, about halfway between the latter
and the anterior edge of the animal and about halfway between
the right margin of the foot and the mid-dorsal line. Limax is a
hermaphrodite, but the reproductive cells do not ripen simulta-
neously, so that the creature functions either as male or as female
at one time. During its female state, the genital opening serves
as a vulva; during the male state, the penis is protruded through
it and appears as a cylindrical body with a triangular terminal
fin. The position of the pneumostoma and of the genital opening
is characteristic of the genus.
Integument. The integument of Limax is composed of
a single layer of epUhdium and of a dermis. The cuticle produced
by the epithelial cells is very thin and presents numerous pores.
Large gland cells originally belonging to the epithelial layer form
a sub-epithelial layer. Between the gland cells under the epithe-
liiun are pigment cells which belong already to the dermis. The
most important elements of the latter are connective cells and
muscle fibres. An especially large caudal gland is located in the
integimient near the posterior end of the body. The muscular
fibres are especially well developed in the foot.
