THE SKIN AND APPENDAGES 903 
The anterior border has a prominence (Spina helicis) at its lower part, and below 
this it divides into two branches (Crura helicis). One of these continues down to a 
blunt point, while the other turns into the cavity of the concha. The posterior 
border forms a pouch below its middle, and is thick and rounded in its basal parv. 
Here the conchal cartilage bears a pointed process (Processus uncinatus), which pro- 
jects upward and backward. The outer wall of the cavum conche is supported 
by a quadrilateral plate (Tragus) above and a semi-annular cartilage below. The 
concave surface presents several cutaneous folds, and in the cavum conch there 
are ridges and irregular prominences. There are long hairs on the borders, apex, 
and the folds of the concave surface, but the skin of the cavum conche is bare. 
The annular cartilage is a complete ring. The osseous external acoustic meatus 
is wide and extremely short. 
The auricular muscles are thin. The scutularis is extensive and is divisible 
into interscutularis and fronto-scutularis. It partly covers the occipitalis muscle, 
which is oval and unpaired and ends in the fascia of the frontal region. The 
scutulo-auriculares superficiales, ventralis et accessorius, and the cervico-scutularis 
are not differentiated as separate muscles. The cervico-auricularis superficialis 
and the parieto-auricularis both bifurcate and are inserted into the base of the 
concha and the scutiform cartilage. The parotido-auricularis is narrow and almost 
long enough to meet the opposite muscle. The tragicus consists of two parts; of 
these, the lateral one is long and arises fron the border of the mandible above the 
angular process. The helicis and the verticalis auriculz are well developed. 
The tympanic cavity is very roomy, extending ventrally into the large but 
simple cavity of the bulla ossea. The tympanic membrane is extensive and oval. 
The promontory is very pronounced. The auditory ossicles are large. The 
auditive or Eustachian tube is short, and has a fibrous lateral lamina. Its pharyngeal 
opening is an oblique slit situated on the lateral wall of the naso-pharyngeal meatus, 
and is margined medially by a thick mucous fold. The cochlea has three and a 
half turns and is more sharply pointed than in the ungulates. 
THE SKIN AND APPENDAGES 
The skin varies greatly in thickness in different breeds. It is remarkably 
loose on the dorsal aspect of the neck and trunk, where it can be raised in extensive 
folds. The coat is also subject to extreme variation in length, thickness, color, ete. 
The hairs are arranged in groups of three to a large extent. The sebaceous glands 
are best developed in the short and rough haired breeds. They are largest and 
most numerous at the lips, anus, dorsal surface of the trunk, and sternal region. 
The sweat glands are relatively better developed in the long and fine haired breeds. 
The largest are found in the digital pads. Coil glands occur in the skin of the 
perineum and the paranal pouches. In the muzzle glands are absent or very 
scanty. 
On the flexion surface of the carpus and digit there are hairless, cushion-like 
pads. The carpal pad (Torus carpalis) is situated medial and distal to the accessory 
carpal bone. The metacarpal and metatarsal pads (Torus metacarpalis, meta- 
tarsalis) are the largest and are situated behind the distal ends of the metacarpal 
or metatarsal bones and the greater part of the first phalanges. ‘They are somewhat 
heart-shaped, with two unequal lateral lobes, and the apex distal. The metapodio- 
phalangeal joints rest on them when the paw supports the weight. The digital 
pads (Toruli digitales) are oval and are much smaller; they similarly support the 
second digital jomts. That of the first digit is small on the forelimb, and usually 
absent from the hind limb. Each receives two suspensory bands from the tubercles 
1Trautmann has shown that the secretion which appears on the muzzle comes from the 
lateral nasal gland, which is well developed. 
