fore-feet are thicker and more extensive than those of the hind.

2. THE PLANTAR CUSHION on FIBRO-FATTY FROG.--Composed of a fibrous
meshwork, in the interstices of which are lodged fine elastic and
connective fibres and fat cells, this wedge-shaped body occupies the space
between the two lateral cartilages, the extremity of the perforans tendon,
and the horny frog. It offers for consideration an antero-superior and an
infero-posterior face, a base, an apex, and two borders.

The antero-superior face is in contact with the terminal expansion of the
perforans tendon. The infero-posterior face is covered by the keratogenous
membrane, and follows closely the shape of the horny frog, on whose inner
surface it is moulded. It presents, therefore, at its centre a single
conical prolongation, the _Pyramidal Body_, which is continued behind, as
is the horny frog, in the shape of two lateral ridges divided by a median
cleft. The _base_ of the cushion lies behind, and consists of two lateral
masses, _the Bulbs of the Plantar Cushion_. In front these are continuous
with the ridges of the pyramidal body, while behind they become confounded
with the lateral cartilages and the coronary cushion. The _apex_ is fixed
into the plantar surface of the os pedis, in front of its semilunar ridge.
The _borders_, right and left, are wider behind than before, and are in
relation with the inner faces of the lateral cartilages.


H. THE KERATOGENOUS MEMBRANE.

THE KERATOGENOUS, OR HORN-PRODUCING MEMBRANE, is in reality an extension
of the dermis of the digit. It covers the extremity of the digit as a sock
covers the foot, spreading over the insertion of the extensor pedis, the
lower half of the external face of the lateral cartilages, the bulbs of the