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http://www.archive.org/details/cu31924081040085

The Anatomy
of the

Domestic Fowl

By
B. F. Kaupp, M. S., D. V. M.

Poultry Investigator and Pathologist in the North Carolina

Experiment Station, State Department of Agriculture, and the

State College of Agriculture; Formerly Director of Anatomy
Laboratory, Kansas City Veterinary College

Illustrated

Philadelphia and London

W. B. Saunders Company
1918

Copyright, 1918, by W. B. Saunders Company

PRINTED IN AMERICA

To
‘DAN T. GRAY, B. S., A. B., M. S.
‘ Cer, ANIMAL INDUsTRY Division, NortTH CAROLINA
EXPERIMENT STATION ,
As A ToKEN oF RESPECT AND GRATITUDE THIS
VoLumE 1s DEDICATBD
By
THE AUTHOR

FOREWORD

ADVANCED work in the study of poultry husbandry is now being
done in this country, to a greater or less extent, at all the two score
and more Agricultural and other Colleges and Experiment Stations.
From these institutions comes the demand for a text-book on the
Anatomy of the Domestic Fowl. No complete text-book on the
subject, up to the present, has existed. It is with the hope of
meeting the demand that this book is published.

In supplementing the information gathered from the books and
articles listed in the bibliography, the author has spent much time
and effort in obtaining the matter here presented. As this, however,
is the initial complete text on the subject necessarily much remains
to be added and corrected. The author would welcome suggestions
and corrections from any one into whose hands the book may come.

B. F. Kaupp.

Tue Norts CarRoLina STATE COLLEGE OF AGRICULTURE,
West RALEIGH, NortH CAROLINA,
September, 1918.

OSSEOUS STRUCTURE . .

CLASSIFICATION oF BONES.

CONTENTS

OSTEOLOGY

CoMPOSITION OF BONE . .

SKELETON OF THE FowL
‘ Axial Skeleton. . .

Cranium and Face .

Occipital .
Ethmoid

Sphenoid .
Frontal. .
Parietal

Temporal .
Premaxilla
Maxilla_.
Nasal. . .
Lacrimal

Palatine. .

Pterygoid. .

Zygomatic.
Vomer . .

Jugal and Quadrato: jugal

Quadrate .

Inferior Maxilla .
ae beet Bones .

Hyo:

Vertebral oo :
Cervical Vertebrz

Axis ‘
Dorsal Vertebre. . . .
Lumbosacral Vertebre
Eecees! Vertebre

Sternum

Appendicular Skeleton

Shoulder Girdle
Fore Limb. .
Pelvic Girdle
Hind Limb . .

Kinps or Joints. ...
MovEMENTS or JOINTS
LIGAMENTOUS STRUCTURE

ARTHROLOGY

CONTENTS

LIGAMENTS OF:

Ear

Jaw ..

Vertebrz

Ribs . .

Sternum . . ‘
Shoulder-joint:.
Elbow-joint . .
Carpal Joint.

Finger .

Pelvis. .

Hip-joint
Knee-joint
Tibiometatarsal Joint.
TOES) os bap cheese! nay ee

MYOLOGY

Kinps AND STRUCTURE OF MUSCLES
PASCEA: oh os. erg ok gi eat i
‘MuscuLaR NoMENCLATURE

True Dermal Muscles.
Dermo-osseous Muscles .
Muscles of the Head .
Muscles of the Tongue -
Cervical Muscles... . .
Muscles of the Air Passages .
Superior Larynx. .
Inferior Larynx .
Sternal Muscles . . .
Abdominal Muscles. .
Dorsolumbar Muscles.
Coccygeal Muscles. .
Costal Muscles. . . . .
Anterior Pectoral Muscles ,
Pectoral Muscles... .. ..
Muscles of the Scapular Region .
Muscles of the Brachial Region .
Muscles of the Forearm and Hand
Digital Muscles .......
Muscles of the Posterior Limb .
Tibial Group of Muscles
Muscles of the Eye.
Muscles of the Ear .

FUNCTIONS OF MUSCLES.

SPLANCHNOLOGY

DIGESTIVE APPARATUS

Mouth
Tongue..

Pharynx rer SA erie lee

Glands Adjacent to Mouth and Pharynx .

Esophagus ims SC Le, BRS

CHOP ee ee ee
Stomach 2.2.4 6¢ . «#% # % »

Proventriculus . oe Gal ee at og nan es eee : :
Gigzard's eo 2 6 |e B&R ee ee we a we
small Intestines s+ 2 4 ¢ 2.2 6 KS ew we Awe ke we wR aS

- 147

CONTENTS

Cor one Or ae e ink oe

Accessory ORGANS OF DIGESTION. ........ ar
Liver. . isaac “pee apie eNews Gly ye seria eee
Pancreas cane : ee (a eee Rosai
Spleen...

ABDOMINAL AND PELvic CAVITIES is ee

PERITONEUM AND MESENTERY... 0. e172 ee eee

RELATIONS OF THE VISCERAL ORGANS OF THE DomESTIC FowL.

RELATIONS OF THE VISCERAL ORGANS OF THE BABy CHICK

UROGENITAL SYSTEM. . 7 ww ee mae
Urinary Apparatus .

- Kidn

Male Generative Organs
Testicles . . .
Vas Deferens :
Female Generative Organs

Parts of the Oviduct . .
Ligaments of the Oviduct .
DucrLess GLANDS. . .
Thyroid Gland. .
Thymus Gland. .
Adrenal Gland. . .
RESPIRATORY APPARATUS... ..
Nostrils and Nasal Chambers
Pharynx and Superior ieee
Trachea.
Inferior Larynx ‘ ‘
Bronchi and the Lungs $
Air-sacs ‘ ‘

ANGIOLOGY
CIRCULATORY APPARATUS... .....

Structure of the Heart i Z
Blood-vessels . . ~~... 00... we eee
Structure of the Capillaries and Arteries
Structure of the Veins
Arterial Trunks
Branches of:
Arteria Brachiocephalica . . .
Arteria Carotis Cerebralis Interna .
Arteria Carotis Externa
‘Arteria Carotis Facialis .
Aorta Posterior

Venous Trunks . sats es et ie ile Sees

Branches of:
Venez Cave Anteriores . . .
Vena Jugularis. :
Vena Occipitalis Externa
Venous Sinuses of the Head .
Veins of the Brain Cavity

Vetmsotthe NE o x. hea aw HORA Eee we

14 CONTENTS

PAGE

Branches of the Vena Subclavia : is tae od LSE 243
Veins of the Dorsal Region . . ‘ fs heh 243
Veins of the Thorax . Sree ok Boe ae 244
Veins of the Fore Limb . deck, eden . 245
Branches of the Iliaca_ . Ne ties 246
Branches of the Vena Iliaca Interna Eat G . 247
Posterior Vena Cava . . 2 247
Veins of the Posterior Extremity. 6 3 248
Branches of the Vena Cava Posterior . . 248
Veins of the Caudal Region and Pelvic Cavity. : 250
Veins of the Truncus Vena‘Iliaca Communis. 252
Visceral Veins of the Posterior Vena Cava. 252
Lymphatic System. . 254
BLooD AND ITS FUNCTIONS : 257
FATE OF THE ERYTHROCYTE 3 . 201
NEUROLOGY

NERVOUS SYSTEM 264
Cranial Nerves. 265
Olfactorius : 265
Opticus. . . P 267

Motoris Oculi ; 267
Patheticus. , ale 268
Trifacialis . 268
Abducentes . . . 270

Facialis and Acousticus ; . 271

Vagus Group . . ‘272
Glossopharyngeus ‘ 272

Vagus or Pneumogastricus. 273
Accessorius Spinalis 274
Hypoglossus . . 274

Spinal Cord. . . 275
Structure of the Cord. : : 275
Structure of the Nerve Trunks and Ganglia . 277

Spinal Nerves . 281
Brachial Plexus . . 282
Lumbosacral or Crural Plexus : 285

Brain .. é 288
Coverings of ‘the Brain 288
Structure of the Brain 289
Divisions of the Brain . 290
Sympathetic Nervous System ‘ ae 207
Functions of the Nervous System 4 ; 300

ESTHESIOLOGY
Sense Organs ‘ Gnarls, waa 303
Sight . Pg abo ted & 308
Hearing. Be Rh gh ao fone - 305
Smell . 2) aN ih BO BOF
Taste. ; 7 aw eS ae FOF
Touch... : ie ee BO"
STRUCTURE OF APPENDAGES. Bk a oe id Bao we Boo
EMBRYOLOGY
SPERMATOGENESIS . ay Rell: A ta. we eae) 243378)

OOGENESIS . ‘ Dyce Gee. ob GGLO

CONTENTS

FERTILIZATION. .. 1... fie Rt Ate Ten ade
OUTLINE FOR LABORATORY STuDy OF THE Cutcx arn he Ay ee
Living Embryo ..........-...22.500084

Preparation for Study of Entire Embryos and Sections . . .

* Points to be Observed in the Study.
DERIVATIVES OF THE GERM-LAYERS. . .
PREPARATION OF STRUCTURES FOR STUDY
Directions for Dissecting Muscles
Directions for Study of the Viscera .
Directions for Study of the Arteries
Study of the Structure of Bones... .......

Special Technic for Dissection of Cranial and Spinal Nerves .

Directions for Study of Soft Structures. ........
To Stain Sections of Liver for Study of Kupffer Cells. . .
To Prepare Anatomical Specimens for Museum
To Make Specimens Transparent. . .. .

EQUIPMENT. FOR THE DISSECTION LABORATORY .

BIBLIOGRAPHY . e koe eee

INDEX . Si ae se. ep ne Sa Gee ae as

ANATOMY

OF THE

. DOMESTIC FOWL

OSTEOLOGY

Osseous Structure.—Bone is structurally modified connective
tissue which has become hard by being impregnated with calcium
salts.

Kinds of Bone Tissue——There are two kinds of bone tissue:
substantia compacta, or compact bone tissue; and substantia spon-
giosa, or spongy, cancellous bone tissue.

Compact Bone Tissue——The compact bone tissue forms the hard
outer layer of all bones. It is thickest in the shaft and becomes thin
toward the extremities. Through the compact bone tissue approxi-
mately parallel with the longitudinal axis of the bone, run canals
called Haversian canals, through which pass blood and.lymph ves-
sels for the nourishment of the bone and nerves. The Haversian
canals are surrounded by concentric lamell@. The spaces between
the cylinders thus formed are filled with interstitial lamelle@; and
both the exterior surface of the bone and the interior surface sur-
rounding the medullary canal, are built up of peripheral, or circum-
ferential lamellz. Between the lamelle, somewhat irregularly
placed, are minute reservoirs, called Jacune, which contain bone
corpuscles. From the lacune radiate minute canals, or canali-
culi, which maintain circulation through the bone substance, and
which communicate with the Haversian canals. Complex anasto-
moses exist among the canaliculi. Still other channels for the pas-
sage of blood-vessels are Volkmann’s canals which pierce the periph-
eral lamelle, thus allowing vessels to pass from the periosteum to
the Haversian canals. Similar channels afford communication
between the inner Haversian canals and the medullary cavity.

The entire structure composed of an Haversian canal, its sur-

2 17 a

18 ANATOMY OF THE DOMESTIC FOWL

rounding lamelle, lacune, and canaliculi, with their contained
vessels, is called an Haversian system.

Cancellous Bone Tissue-—The cancellous bone tissue forms the
bulk of the short, flat, and irregular bones and of. the extremities
of the long bones. It consists of delicate bony plates and spicules,
which intercross in various directions? The spaces between these
plates and spicules, called cancelli, are occupied by marrow except in
the bones that are pneumatic. The blood-vessels, lymphatics, and
nerves course through this marrow but are not arranged in an Ha-
versian system. =

Bins

Fic. 1.—Longitudinal section of compact bone of the femur of the hen. 1,
Haversian canals. 2, Lacune with their canaliculi.

The Periosteum.—Covering the surface of bone, except at the
articular surface where it is covered with cartilage, is a membrane,
the periosteum, which consists of two layers: an outer, fibrous,
protective layer, and an inner, cellular, osteogenic layer. The outer
layer consists principally of -white fibrous tissue. ‘The inner layer
contains many more corinective-tissue cells, which gradually be-
come more closely aggregated’ as we proceed toward the osseous
surface; but there is no sharply defined line of demarcation between
the,two periosteal layers.

OSTEOLOGY 19

ai

Fic. 2.—Transverse section of compact bone of the femur of the hen. 1, The
lacune and carialiculi. 2, The periosteum.

Fic. 3.—Transverse section of compact bone of the femur of the hen showing
the lacune and canaliculi under high magnification.

20 ANATOMY OF THE DOMESTIC FOWL

The periosteum is firmly attached to the bone by trabeculz. of
fibrous tissue, called the fibers of Sharpey. These fibers of Sharpey
penetrate the bone at right angles to its surface and carry blood-
vessels.

Marrow.—There are two kinds of marrow: yellow, or medulla
ossium flava,.and red, or medulla ossium rubra.

The yellow marrow occurs in all bones except the femur and proxi-
mal portion of the tibia of adult fowls. It is composed of a network
of fibrous tissue carrying blood-vessels, fat cells, and myelocytes, or
marrow cells.

The red marrow is found throughout the femur and the proximal
portion of the tibia, and in a few of the pelvic bones and vertebree
in the adult fowl, and in certain other bones of the baby chick.
Red marrow consists of a delicate network of connective tissue
supporting a dense capillary plexus, a small amount of fat, and
numerous cells. The cellular elements of red marrow consist of
marrow cells which contain large nuclei and possess ameboid move-
ment, red blood cells, giant cells containing one or more nuclei, and
various kinds of leucocytes, including eosinophiles, mast cells, and
also osteoclasts. ,

Growth of Bone.—In the baby chick, only the shaft and a portion
of the extremities of the long bones are thoroughly ossified, the ex-
treme ends, and of the femur most of the articular head, being
cartilaginous. The bones grow in length by an increase in the carti-
lage, the cartilage gradually becoming ossified. Growth in diameter
is accomplished by the constant deposition of new layers of bone
beneath the periosteum. During this process the osteoclasts ab-
sorb the bone from within. The formation of the marrow cavity is
thus effected.

Classification of Bones.—The bones of the fowl are classified
as long, short, flat, and irregular.

Long Bones.—The long bones occur in the legs and wings, where
they serve as levers to sustain weight and make locomotion possible.
A long bone consists of a shaft and two extremities. The superior
is ‘called the proximal and the inferior the distal extremity. The
expanded articular surfaces in forming joints with adjoining bones
afford ample space for the attachment of ligaments. The shaft is
cylindrical and hollow.

Short Bones—Short bones occur in the feet and in the wings.
Their structure is similar to that of the long bones.

OSTEOLOGY 21

Flat Bones.—The flat bones occur where extensive protection
is needed, as in the cranial region; or where large surface for muscular
attachments is needed, as in the costal and pelvic regions. Flat
bones are made up of two thin layers of compact bone with a vari-
able amount of cancellous tissue interposed.

Irregular Bones——The irregular bones include ,the vertebre,
the patella, and the carpal bones.

Composition of Bone.—Bone consists of organic and inorganic
matter. Organic matter gives toughness and elasticity to the bone,
and inorganic matter hardness. The organic substance of bone is
called ossein. When boiled in water ossein is resolved into gelatin.
The following tables! give the results of an analysis of the femur,
fresh, of a mature hen.

Fresh femur:

Waters oie cnc omand ea nape ameter 18.23 per cent.
Diy Matter i223) 3.4 5505 orn taaee oe mi oem emcee 81.77 per cent.
Dry matter:
Oreanic:matterisesk.cecangnas capes eee een 4 63.09 parts
Inorganic matter........... 0.00. cece eee eee ee 18.68 parts
Salts in dry matter:
Galeitint's 253,60 teas iis Soo sginy BR Panwiudl aedan bubies . 6.970 per cent.
Magnesium....... LDA LER SA OG CGC ne aN 0.283 per cent.
POCASSHUM. jaca ieee cpnaes dundeane aed Montana eRaunauaneies ©.004 per cent,
SOSH Ts i acescnecemninras cq ecbeaielee gen seee ascnieds Bm anterior 0.276 per cent.
MODs sues ena Sencha n one weeny a ew Paes wegen tome y 0.020 per cent.
Phosphorusei22:ciy 22s pegig agate vaswe eset 3-210 per cent.
Stl phir isons ecysnand 3 weeny 68 aeutaes Be nee 0.085 per cent.
Chlorine sews si craeeeewmae 2s <eesae se eeeeaees 0.520 per cent.
Carbon dioxid .................. 000 cece ee eee 0.550 per cent.

The inorganic matter of the femur of the hen consists of 18.68
parts or 22.84 per cent. of dry matter, and the organic matter of
77.16 per cent. Stated in other words the femur, including its
contained marrow, consists of organic and inorganic matter in the
ratio of 3.4, approximately, to 1.

The Skeleton of the Fowl.—The skeleton of a bird is remarkable
for the rapidity of its ossification. It is worthy of note that other
parts of the bodies of adult birds also become ossified. Among such
parts are the tendons of the muscles of the legs, of the feet, and of the

1 Greatful acknowledgment is hereby made to Dan M. McCarty, Chemist,
AnimaljIndustry Division, North Carolina Agricultural Experiment Station, for
this analysis.

22 ANATOMY OF THE DOMESTIC FOWL

neck; the plates of the corneal margin of the sclerotic tunic of the
eye; and the stapes of the ear. Ossification in birds at the attach-
ments of the semi-lunar valves of the aorta and of the pulmonary
artery has been reported by Owen.

The bony structure is compact, and the bones contain a greater
proportion of phosphate of lime than do the osseous structures
of mammals. Especially is this the case in those parts of the
skeleton which are permeated by air.

Tue DIvIsIONS OF THE SKELETON

Cranium
The Skull

Face
The Axial skeleton Cervical region
Ribs

Dorsal region { Sere

The Vertebral column é
Lumbar region

Sacral region
Coccygeal region
{ Scapula
Shoulder girdle Coracoid
Clavicle
( Arm {Humerus
{ Radius

Fore limb Potearm

| Ulna
Carpus
The Appendicular skeleton Hand ; Metacarpus
-| Phalanges

ae Tlium
Pelvic girdle Taciivne

(Hip bone) | Pubis
f Thigh {Femur
Tibia

Fibula
{ Metatarsus
Foot |

Hind limb | Leg |

Phalanges

The bodies of birds contain many air reservoirs to make them
light that flying may be more easy. Many bones have their weight
in proportion to size and strength thus greatly reduced. In very
young birds the cavities of bones contain, instead of air spaces,
loosely arranged red marrow, which is in most bones later absorbed.

OSTEOLOGY 23

The air reservoirs in bones are most capacious in the best flyers.
In the non-flyers more of the bones retain their red marrow.

The bones supplied with air spaces are relatively Jarger’ than
in mammals, and are provided with small transverse osseous columns
which cross in different directions and from side to side. These cross
beams give stability to the thin wall of the bone. The membranes
lining these cavities are very vascular.

THE AXIAL SKELETON
THE SKULL

The skull is divided into the cranial and facial portions. In
these parts we find present 31 bones: one occipital, two parietal, two
frontal, one ethmoid, one sphenoid, and two temporal; all of which
constitute the cranial group; two premaxillary, two maxille, two
nasal, two lacrimal, two palatine, two pterygoid, two zygomatic,
one vomeral, the two jugal, and two quadrato-jugal, which constitute
the facial group; two quadrati and one inferior maxillary, which
constitute the inferior jaw group.

The peculiarities of the skull‘are the long os incisivum and the
single condyle located on the occipital bone just below the foramen
magnum. The condyle articulates with the atlas.

The head of the bird is small in proportion to the size of the
body, and in front it is conical in shape.

THE CRANIUM :

The cranial cavity, or cavum cranii, incloses the brain with its
membranes and vessels.

The dorsal wal], or roof, is formed by the frontal and the parietal
bones. In the median line of the cerebral portion is the internal
parietal crest. The roof of the cerebellar portion is marked centrally
by a groove.

The posterior wall of the cerebellum is formed by the occipital
bone. :

The lateral wall is formed chiefly by the temporal bone. It is
marked by a ridge which divides the cavity into the cerebral and
cerebellar compartments. The cerebral portion is marked by a
depression which receives the optic lobes. A crest divides this
cavity from the optic portion. The walls are marked by digitations
and vascular grooves.

24 ANATOMY OF THE DOMESTIC FOWL

Fic. 4.—The skeleton of the domestic fowl. 1, Os incisivum. 2, External
nasal opening. 3, Os nasale. 4, Os lachrymale. 5, Lamina perpendicularis.
6, Osdentale. 7, Ospalatine. 8, Os quadrato-jugal. 9, Os pterygoideum. 10,
Os quadratum. 11, Os articulare. 12, External auditory canal. 13, Atlas.
14, Os carpi radiale. 15, Radius. 16, First finger. 17, Os metacarpus. 18,
Second finger. 19, Third finger. 20,Oscarpiulnare. 21, Ulna. 22, Humerus.
23, Thoracic vertebre. 24, Scapula. 25, Osilium. 26, Foramen ischiadicum.
27, Caudal vertebre. 28, Pygostyle. 29, Foramenobturatum. 30, Osischium.
31, Processus uncinatus. 32, Vertebral rib. 33, Os claviculum or furculum.
34, Oscoracoideum. 35, Osfemoris. 36, Ospubis. 37, Body of sternum. 38,
Lateral internal process of sternum. 39, Costal process of sternum. 40, Sternal
crest, cristi sterni, or keel of breast-bone. 41, Sternalrib. 42, Lateral external

OSTEOLOGY 25

The ventral wall, floor, or basis cranii interna, may be regarded
as forming five fosse. These are: one anterior, one middle, one
posterior, and two lateral. The anterior fossa supports the frontal
and olfactory parts of the cerebrum. It lies at a higher level than
the middle fossa. The middle fossa, or fossa cranii media, is circular
in outline and extends into the lateral fossze which lodge the ol-
factory lobes. Just back of the middle fossa is the sulla turcica,
upon which rests the pituitary body. The posterior fossa, or fossa
crant posterior, lodges the medulla oblongata.

Bones of the Cranium (Figs. 4, 6, 7, and 8).—The bones of the
cranium fuse early in the chick’s life. The sutures uniting the
bones can usually be seen in the fetus or in the baby chick soon
after it emerges from the shell. The major portion of the cranial
bones become entirely fused. Each cranial and each facial bone
ossifies from a distinct center or centers.

The cavity for the cerebrum is much larger than the cavity
for the cerebellum. The cranial cavities in birds are relatively
larger than in mammals. The bones are designated as in mammals.
There are three single bones, the occipital, the ethmoid, and the
sphenoid. Those in pairs are the frontal, the parietal, and the
temporal.

The Occipital. Location—The occipital bone or os occipitale,
is situated at the posterior part of the cranium, of which it forms the

posterior wall. This part is called the base of the cranium. The
_ occipital bone articulates with or touches inferiorly, the sphenoid,
laterally, the temporal, and superiorly, the parietal.

Development.—The occipital bone is developed from four centers
of ossification; the dorsal, or os occipitale superius, two lateral, or
ossa occipitales laterales, and the ventral, or os occipitale inferius,
all of which may be seen distinct in the baby chick (Fig. 5, Part II,
No. 1).

Description In the center of the occipital bone is the foramen
magnum. Through this foramen the spinal cord extends into
the cranial cavity and connects with the medulla oblongata.. The
occipital bone has a single condyle, which is located just below the

*
process of sternum. 43, Os fibula. 44, Zyphoid process of sternum. 45, In-
ternal notch. 46, Os patella. 47, Os tibia. 48, Os metatarsus. 49, Second
toe. 50, Fourth toe. 51, Os metatarsale. 52, First toe. 53, Second toe. 54,
Second phalanx of second finger. 55, Os meta carpus. 56, Air opening in
humerus. 57, Hypocledium. 58, External notch. 59, Cervical vertebra. 60,
Foramen oblongum.

26 ANATOMY OF THE DOMESTIC FOWL

x

“TA ST Pe we hh Be FB

Sey

Fic. 5.—Bones of the head and vertebra.

Part I—1, The cranium. 2, The skull cap. 3, The ethmoid bone. 4, The
inferior maxilla. 5, The palatine bone. 6, The quadrato-jugal. 7, The jugal.
8, The superior maxilla. 9, The premaxilla. 10, The horny covering for the
premaxilla. 11, The horny covering for the os dentale. 12, The os quadratum.
13, The nasal bone. 14, The pterygoid.

Part II.—1, The os occipitale (1, dorsal; 2, two lateral; 3, ventral portions
and 4,foramenmagnum). 2, The fourteen cervical vertebre. (1, atlas; 2, axis).
3, The seven dorsal vertebre. 4, The fourteen lumbo-sacral vertebre. 5, The
seven coccygeal vertebre. 6, The pelwis (1, ilium; 2, ischium; 3, pubis; 4, cotyloid
cavity or acetabulum). 7, The vertebral column complete from the baby chick.
8, The parietal bone. 9, The temporal bone: 10, The frontal bone.

OSTEOLOGY i 27

foramen magnum and articulates with the atlas. At the base of
the condyle a small subcondyloid fossa receives the body of the atlas
during extreme flexion of the head. In the center of the lateral
wing of the occipital bone there is a small foramen through which
passes the hypoglossal nerve. Somewhat laterally from this foramen
there 1s an vpening through which the vagus, or pneumogastric

Fic. 6.—View of the frontal region of the skull of a hen. 1, Parietal. 2 9

srontal. 3, Nasal. 4, Premaxilla. 5, Temporal. 6, Inferior jaw. 7, Jugal
bone. cs co a Sy

nerve passes. Laterally from these is the canalis caroticus et ju-
gularis. Between the os occipitale superius, or dorsal portion,
and the ossa parietalia is a space to which ligaments are attached,
called the fontanel.

The Ethmoid. Location—The ethmoid, or os ethmoidale,
forms the anterior wall of the cranium, and the orbital septum.
It is related anteriorly with the vomeral, superiorly with the nasal

28 ANATOMY OF THE DOMESTIC FOWL

and frontal, posteriorly with the temporal, and inferiorly with the
sphenoid, and palatine.

Description—The ethmoid consists of a perpendicular and a
horizontal lamina. The perpendicular lamina, located between
the orbital cavities, is called the septum interorbitale. On each side
of the septum interorbitale and near the superior orbital roof are
two foramina for the passage of the olfactory nerves. In the hori-
zontal plate, which forms the anterior cranial wall, are located the
optic foramina through which pass the optic nerves.

Fic. 7.—Side view of the skull of a hen. 1, Lamina perpendicularis. 2,
Foramen for the passage of the nerve of smell. 3, Foramen for the passage of
the optic nerve. 4, Nasal bone. 5, External nasal opening. 6, Premaxilla
7, Os dentale. 8, Superior maxilla. 9, Os jugal. 10, Os quadrato-jugal. 11,
Os quadratus. 12, Pterygoideus. 13, Osarticulare. 14, Inferior maxilla. 15,
Temporal. 16, External auditory canal. 17, Parietal. 18, Frontal. 19, Pala-
tine. 20, Orbital process, posterior to which is the processus zygomaticus.
21, Interorbital foramen and optic foramen for passage of optic nerve.
22, Attachment for inferior oblique; 23, for superior oblique; 24, for levator
palpebre superioris; 25, for internal rectus; 26, for superior rectus; 27, for external
rectus; 28, for inferior rectus; 28, for inferior rectus; 29, for depressor palpebre
inferioris; 30, for orbicularis palpebrarum; 31, for tensor tympani; 32, for circum-
concha.

The Sphenoid. Location—The sphenoid, or os sphenoidale,
forms the floor of the cranial cavity and articulates with or touches
posteriorly the occipital, laterally the temporal, and anteriorly the
palatine, and ethmoid.

Description.—The sphenoid bone, the largest part of the cranial
floor, is formed by the fusion of the nasal and the cranial parts. Itis
a three-cornered bone with two, thin, broad wings. These wings
are divided into two portions, orbital wings, or ale orbitales, and

OSTEOLOGY 29

temporal wings, or ale temporales. The temporal wing forms a
cover for the Eustachian tube trumpet, and for the canal coming
from the sella turcica, which latter gives passage to the intracranial
carotid artery. The orbital wing forms the lower portion of the
posterior wall of the orbital cavity, and lies directly before the os
petrosum or temporal bone where the second and third branches
of the fifth pair of cranial nerves emerge from the cranial cavity.

Anteriorly the sphenoid has a foramen for the passage of the
Eustachian tube, the tuba auditiva, and also a sharp-pointed projec-
tion, the nasal portion, called the rostrum.

The Frontal. “Location.—The frontal bones, or ossa frontales, two
in number, form the forehead, a portion of the nose, and a portion
of the roof of the orbital cavities. They are related posteriorly with
the parietal, laterally with the temporal and zygomatic, and ante-
riorly with the nasal and premaxillary. They touch inferiorly the
ethmoid.

Description —Each of these bones has a processus orbitalis which
is seen at the outer margin of the posterior and upper orbital wall
and just in front of the, zygomatic process of the squamous
portion of the temporal. The frontal bone forms the anterior
portion of the superior wall of the cranial cavity. The two bones are
thin, flat, and meet at the median line of the forehead. The external
surface is convex. The inner surface has a ridge located longitudi-
nally and in the center the bone becomes narrow anteriorly.

The Parietal. Location—The parietal bones, or ossa parietalia,
two in number, form the posterior part of the roof of the cranial
cavity. They meet in the median line and are related posteriorly
with the occipital, anteriorly with the frontal, and laterally with the
temporal bones.

Description—tThe parietal bones are short and very broad (Fig.
5, Part II, No. 8). Each bone is quadrilateral in outline and has
two surfaces, four borders and four angles. The external parietal
surface is convex and smooth and the internal, cerebral surface is
concave. :

TheTemporal. Location —The temporal bones, or ossa temporales,
two in number, are located at the lateral portion of the cranium, and
aid in the formation of the cranial wall. The temporal boneis related
posteriorly with the occipital, superiorly with the parietal and fron-
tal, externally with the quadratus, anteriorly with the ethmoid, and
inferiorly with the sphenoid.

30 ANATOMY OF THE DOMESTIC FOWL

Description.—The temporal bones consist of the fused squamous
and petrous temporals; they contain the essential organs of hearing.
The squamous portion of the temporal bone possesses the long
thin zygomatic process sometimes called the posterior orbitalis.
It forms a small flattened tongue, directed forward, sometimes
free, and at other times united by its superior border to the

Fic. 8.—Inferior view of the skull of a hen. 1, Occipital. 2, Foramen mag-
num. 3, Occipital condyle and just below the basi-occipital. 4, Foramen for
the passage of the hypoglossal nerve. 5, Foramen for the passage of the vagus.
6, Canalis caroticus and jugulare. 7, Sphenoid. 8, Temporal wings of the
sphenoid. 9, Foramen auditiva. 10, Os articulare. 11, Os angulare. 12,
Vomer. 13, Osdentale. 14, Pterygoid. Py

summit of the orbital process. This is especially true in the turkey.
This process is seen near the lower outer portion of the posterior
orbital wall. The squamous portion is also provided antero-
laterally with an articular facet which articulates with the quadrate
bone. The large portion of the temporal bone lies on the side of

OSTEOLOGY 31

the cranium superior to the ala sphenoida temporale. It extends
outward and anteriorly over the rims of the petrosum and ala
sphenoida orbitale. The squamous part forms the upper three-
fourths of the cochlea; the inner auditory canal, the upper part of
the fenestra ovalis, the anterior vertical and the outer semicircular
canal, and the lower part of the posterior vertical semicircular canal.

The petrous portion forms the posterior wall of the foramen
ovale-and the fenestra ovalis in which lies the columella. The
fenestra ovalis and the fenestra rotunda are the only two entrances
into the labyrinth. In this region may be seen the fusion line
between the os petrosum and the os occipitale. Superiorly and
posteriorly the petrous portion touches the external parietalia
and occipitalis; infero-laterally it unites with the basi-sphenoid-
The outer rim of the foramen ovale ‘is broadened by the ala sphen-
oida and mesially -by the basi-sphenoid. This foramen gives exit
to the second and third divisions of the fifth pair of cranial nerves.

The lateral surface of the temporal bone presents a short. tube,
the external acoustic process, or processus acusticus externus, -to
which is attached the concha of the ear. The process is directed
outward. Its lumen, the external ‘acoustic meatus, or meatus acus-
ticus externus, conducts to the cavity of the middle ear in the bare
skull, but is separated from it by the tympanic membrane in the
natural state.

BONES OF THE FACE

The bones of the face, or ossa faciei, are the premaxillary, or
upper mandible, the maxille, the nasal, the lacrimal, the palatine,
the pterygoid, the zygomatic, the vomeral, the jugal and the
quadrato-jugal. The vomer is single, the others are paired. In the
inferior maxillary group there are the quadrati, and the inferior
maxillary, or lower mandible. The turbinated and hyoid bones
are also discussed with the bones of the face.

The beak consists of the anterior portion of the upper and lower
mandibles which are covered with a horny structure.

The Premaxilla. Location—The premaxille, or ossa incisiva,
or mandibular structures, are located in the extreme anterior
facial region. .

‘Description—The premaxille are long and the anterior end
is pointed. Each consist of two lateral halves which become fused
before the chick is hatched. They partly circumscribe the openings

32 ANATOMY OF THE DOMESTIC FOWL

into the nose. This bone is the base of the upper portion of the
beak and determines its form. It forms the anterior walls of
the nasal cavity. It has between the nasal bones, two processes
which extend back to the anterior point of the cerebral cavity.
The posterior part of the incisivum and nasale are flat, thin, and
elastic. The extensions then are the processus maxillaris, the
processus palatinus, and the processus frontalis, the first of which
forms part of the jaw rim, the second, which aids in forming the
gum plate, and the last which reaches to the anterior portion of the
cranial wall.

The Maxilla. Location —The superior maxillaries, or ossa maxil-
lares, two in number, form the floor of the upper beak, a part of
the palatine roof and nasal walls.

Each maxilla borders laterally the premaxilla and the nasal;
inferiorly, the anterior point of the palatine; and posteriorly, the
jugale.

Description—The maxille are thin, flat, bones. They have
three borders and three angles. The palatine processes of the two
bones do not meet in the median line, which results in a cleft in
the median palatine region. The bone-like gums are formed partly
by the palatine processes but more largely by lateral wings of the
os incisivum. Each maxilla has posteriorly a yoke-like extension,
superiorly a small extension, and also a palatine process. The
latter articulates by a facet with the vomer

The Nasal. Location—The nasal bones, or ossa nasalia, two
in number, are located in the lateral facial region. The nasal bone
articulates posteriorly with the frontal; laterally, on the inner
border, with the processus frontalis of the premaxilla, and on the
outer border with the lacrimal; and inferiorly with the premaxilla,
maxilla, jugale, and vomer.

Description—The nasal bone, or os nasale, is broad, flat, and
elastic and forms the posterior wall of the nasal opening. Under
this bone is located the infraorbital sinus.

There are three extensions: first, the processus intermaxillaris,
which forms the upper wall of the nasal cavity; second, the processus
maxillaris anterior, directed downward and forward, which fuses
with the maxillary bone and forms the posterior rim of the nasal
cavity; and third, a posterior processus frontalis, which lies parallel
with the ethmoid..

The Lacrimal. Location.—The lacrimal bones, or ossa lacrimalia,

OSTEOLOGY ~ 23

two in number, are located at the outer border and at the junction
of the processus frontalis of the nasal, with the frontal bone.

Description—The lacrimal bone is small, and rather filiform.
They become fused with the nasal and the frontal bones, forming
part of the margin of each.

The Palatine.—Location. The palatine bones, or ossa palatina,
two in number, enter into the formation of the inner part of the bony
gum and hard palate, or roof of the mouth. They form the support
for the hard palate. Each palatine articulates posteriorly with
the rostrum, or nasal portion of the sphenoid, and with the pterygoid;
and anteriorly with the. maxilla.

Description—The palatine bone is curled posteriorly and is thin
at the upper portion and thick at the lower border. Anteriorly
it has a long rather filiform projection.

The Pterygoid. Location—The pterygoid bones, or ossa ptery-
goidea, two in number, are located back of the region of the
posterior nares. They extend diagonally outward and backward
from the median region of the sphenoid rostrum to the quadrate
bone. They articulate anteriorly with the sphenoid rostrum and
the palatine, and posteriorly with the quadrate.

Description—The pterygoid bones are slender and cylindrical,
and are expanded at the ends into an articular facet.

The Zygomatic. Location The zygomatic, or ossa zygomatica,
two in number are situated below the orbital cavity and extend
from the maxilla to the quadrate bone.

Description——The zygomatic is small, slender, rod-shaped, and
forms the lateral portion of the upper jaw. The anterior portion
of the zygomatic represents the jugal and is fused with the max-
illa and with the anterior processus maxillaris of the nasal bone,
the maxilla, and the posterior portion, the quadrato-jugal, which
articulates with the quadrate bone.

The Vomer. Location.—The vomer is located in the median
nasal septum. It articulates with the rostrum of the sphenoid,
being connected to it by a mass of ligaments. It touches ante-
tiorly the posterior portion of the maxilla.

Description.—The vomer is a median bone and aids in the forma-
tion of the septum nasi. It consists of a thin plate, thickest pos-
teriorly and diminishing toward the anterior edge.

The Jugal and Quadrato-jugal——The jugal and quadrato-jugal
are united forming a long slender cylindrical bone called the zygo-

3

34 ANATOMY OF THE DOMESTIC FOWL

matic, lying at the outer side of the upper jaw. They have been
described under zygomatic, which see.

The Quadrate. Location—The quadrate bones, or ossa quadrata,
two in number, are located antero-laterally to the temporal bones.
Each articulates inferiorly with the posterior articular portion, or
pars articulare, of the inferior maxilla and infero-laterally with
the quadrato-jugalare portion of the zygomatic. It articulates
antero-internally with the pterygoid and supero-posteriorly with
the temporal.

Description The quadrate bone is anvil-like in shape. It
has an anterior process, the orbital process, for muscular attach-
ments, and posteriorly it affords attachment to the ear drum.

-The Inferior Maxilla. Location—The inferior maxilla, lower jaw,
or os maxillare inferius, also called the mandibular bone, or pars
dentis, is analogous to the lower jaw of mammals. It articulates
posteriorly with the quadrate bone.

Description.—The inferior maxilla is the largest bone of the face.
It is made up of a right and a left limb which are separate in the fetus
and which unite subsequently anteriorly, forming the inferior por-
tion of the beak. Each limb of the jaw is developed from five ele-
ments: the pars articularis, which forms the jaw-joint and, expanded,
articulates with the quadrate bone; the pars angularis, lying just in
front of the pars articularis; the pars supra-angularis, a slender bone
lying just above the angularis; the splenial, a thin plate of bone,
lying along the inner surface of the mandible; and the pars dentalis,
which forms the anterior portion of the jaw.

The Turbinate Bones. Location—The turbinate bones, or ossa
turbinata, six in number, are attached to the lateral walls of the
nasal cavity (Fig. 26, No. A,1 and2). In eachnasal cavity thereare
three turbinate bones, one anterior and two posterior. Of the two
posterior the upper one lies supero-posterior to the inferior one.
The turbinate bones are attached to the lateral nasal walls, project
into the cavity and thus greatly diminishing its extent.

Description—Each turbinate bone is composed of a very thin
lamina, finely cribriform in many places, and in the fresh state,
covered on both sides with mucous membrane. These bones are
curled and partly membrano-cartilaginous structures which give
greater surface in the nasal passage for mucous membrane in which
the olfactory nerve terminal filaments are distributed.

OSTEOLOGY 35

The Nasal Cavity—The nasal cavity, or cavum nasi, is a lon-
gitudinal passage which extends through the upper part of the face.
It is divided into right and left halves by a median septum nasi.
Its walls are made up of the premaxilla, maxilla, nasal, vomer, and
palatine bones.

The Hyoid Bone. Location.—The hyoid bone, or os hyoideum,
is situated chiefly between the rami of the mandible, but its upper
part extends around the outer margin of the base of the skull. The
hyoid bone does not articulate with any bones of the skull, but is
firmly attached by strong fibrous structure.

Description—The hyoid bone consists of the following parts:
the body, or basi-hyal, which is subcylindrical and presents in front
a trochlear articular surface, convex transversely, and concave
vertically for articulation with the ewer-shaped portion of the glosso-
hyal. The anterior free portion, or lingual process, is called the
glosso-hyal, or entoglossal bone. The lingual process gives support
to the muscular and fibrous structures of the tongue. On either
side of the basi-hyal there is a limb passing posteriorly along the
side of the superior larynx, extending upward along the outer border
of the occipital bone. This is the cornu of the os hyoideum and is
divided into two elements, first, the bast-branchial which is bone and
articulates with the basi-hyal, and the second, the cerato-branchial,
cartilaginous in structure. In the center and projecting backward
from the body of the os hyoideum is a spur process called the uro-
hyal, partly bony and partly cartilaginous, and which rests upon
the superior larynx.

THE VERTEBRAL COLUMN

The vertebral, or spinal column consists of 42 bones, as shown in
the following table:

Cervical region.....—... Siadsnsuase ailPidacngustincs: neagk aeameians 14
Dorsal Pepton.cs seca doc malay ena n acvnmad nam dommes s 7
Lumbo-sacral region.......... 00000000. 14
Coccy geal LEGION eras secs vaterctascndranninanaegeny pietaahow 7

Totals suse wv cerwman sano weeny sauuEdsnne saawe 42

Many of the bones of the dorsal and lumbo-sacral regions do not
have free articulations. The cervical and coccygeal alone have free
movements.

The Cervical Vertebre (Fig. 4, No. 59; Fig. 5, Part II, No. 2).
Location.—The cervical vertebre form the neck of the fowl.

36 ANATOMY OF THE DOMESTIC FOWL

Fic. 9.—Os hyoidum and tongue muscles. 1, Glosso-hyal. 3, Basi-hyal. 4,
Basi-branchial element of the cornua. 5, Cerato-branchial element of the
cornua. 6, Uro-hyal or spur process. 7, Genio-hyoideus. 8, Cerato-hyoideus
showing the slender tendon. 9, Hyoideus transversus. 10, Hyoideus,trans-

versus.

OSTEOLOGY 37

Description—The long cervical section of the spinal column is
S-shaped and is made up of fourteen vertebre. The anterior seg-
ments move freely forward, the middle ones backward and the pos-
terior ones forward, allowing the S-shaped curve of the neck. The
neck is flexible so that it is possible for the beak to reach the coccy-
geal oil gland. The bird is enabled to reach the feathers on all parts
of the body to cleanse and oil them.

The Atlas. Location—The first cervical vertebra is called the
atlas. Anteriorly it articulates with the single condyle of the oc-
cipital bone. Posteriorly it ‘articulates with the axis, or second
cervical vertebra.

Description—The atlas is the smallest of the cervical vertebra
and is ring-shaped. The anterior articular surface, half-moon
in shape, forms a deep articular cavity. The joint, called a ball-
and-socket joint, makes possible movements in all directions. The
condyle of the occiput also touches an articular end of the odontoid
process of the axis, or second cervical vertebra. Posteriorly there
projects from the atlas two small lateral wings possessing articular
facets which articulate with similar facets on the lateral wings of
the axis. Posteriorly the body of the atlas is also provided with an
articular surface which articulates with a similar surface on the
anterior portion of the body of the axis.

The Axis. Location—The axis is the second cervical vertebra.
It articulates anteriorly with the atlas, and by a facet on the extreme
anterior end of the odontoid process, with the condyle of the oc-
cipital bone. Posteriorly it articulates with the third cervical
vertebra.

Description—tThe body of the axis is short. The upper anterior
portion of the body of the axis is provided with a tooth-like process
called the odontoid process. There are two anterior lateral wings
provided with small articular facets which articulate with similar
facets of the atlas. The anterior surface of the body of the axis
forms a true articulation with the body of the atlas.

The axis is provided with a superior and an-inferior spine. There
are two posterior articular processes which articulate with the
prezygapophyses, or anterior articular processes, of the third cervical
vertebra. The posterior part of the body of the axis forms a true
articulation with the body of the third cervical vertebra.

Other Cervical Vertebree.—Beginning with the axis, the body
of which is relatively short, the body of each succeeding vertebra

38 ANATOMY OF THE DOMESTIC FOWL

is longer than that of the preceding. The articulations of each
vertebra with adjoining vertebre are effected by means of di-
arthrodial facets, convex in one direction and concave in the other.

Between the bodies of the vertebra are pads of fibrous cartilage.
Above these bodies and inferior to the neural spines extends through-

Fic. 10.—A. Diagram of three first dorsal vertebre and scapular arch-side view.
B. Diagram of section through the hemal arch.

A. 1, First dorsal segment. z, Second. 3, Third. 4 and 5, Hemal arches.
6, The pleurapophyses or floating ribs. 7, The third pleurapophyses or dorsal
vertebral rib articulating with the hemapophysis or sternal rib, 8, and this in
turn with the wing of the sternum form a hemal arch. 9, The sternum. 10,
Intervertebral foramen through which the nerves pass. 11, Articulation with
the body of vertebra parapophyses. 12, Articulation with transverse process
or diapophyses. 13, Oblique process or zygapophysis. 14, The epipleural
appendage.

B. 1, Hemal or inferior spine (hypapophysis). 2, The neural arch. 3, The
pleurapophyses or rib. 4, The superior or neural spine or neurapophysis which
aids in the formation of the anapophyseal ridge. 5, Parapophyseal surface for
head of rib. 6, Tubercle of rib articulating with the diapophysis. 7, Lamina
of neurapophysis. 8, Centrum. 9, Hemal arch.

out the spinal column the large xeural cagal which is occupied by
the spinal cord. Between the vertebral segments the neural canal
is exposed superiorly, since here the neural arches do not completely
bridge the canal. These spaces are protected by intervertebral
ligaments.

In addition to the superior neural spines and the inferior spines,

OSTEOLOGY 39

from the body of the vertebra project lateral processes, and anterior
and posterior oblique processes.

All cervical vertebra except the atlas and the axis are made up of
the following parts: a body, or centrum, a neural canal, a neural
arch, a superior dorsal, or neural spine, or neurapophysis, which
in most cervical vertebre is only slightly developed, two oblique
processes, or zygapophyses, two transverse processes, or diapophyses
(Fig. 10, No. 12) and in some vertebre two tubercles, or anapophyses
above the posterior zygapophyses. The prezygapophyses are
directed upward and inward; the postzygapophyses are directed
downward and outward. The inferior spines are only well developed
in the last two or three cervical vertebre.

Between vertebral segments, except the central sacral portion, on
each side, there is an intervertebral foramen (Fig. 11, No. A, 4),
through which pass the spinal nerves. In the central portion of the
sacrum where the vertebre have fused, there are two foramina on
each side for each original vertebra, one located above the other,
the upper giving passage to the sensory branch, the lower to the
motor branch of the nerve.

The Dorsal Vertebre (Fig. 4, No. 23; Fig. 11, A). Location.—
The dorsal, or thoracic vertebre, or vertebre thoracicales, aid in
forming the roof of the chest cavity.

Description.—The dorsal vertebral section is made up of seven
vertebra, with strong short bodies. The first and sixth’ dorsal
segments articulate as do the cervical, by the bodies and oblique
processes. (Fig. 11, No. A, 3, illustrates the oblique processes.)
The seventh dorsal is fused with the first lumbo-sacral vertebra.
The second to the fifth inclusive of the vertebra are fused together,
and the superior and inferior spinous processes are fused into a
prominent plate-like ridge.

The transverse processes of the dorsal vertebre, from the second to
the sixth, are well developed and are bridged over with a thin layer of
bone. The ventral spines are partly fused and form a very promi-
nent and continuous ridge. (Fig. 11, No. A, 1, shows the fused
superior spines; No. 2, the fused inferior spines; and No. 4, the inter-
vertebral foramina.)

The Lumbo-sacral Vertebre (Fig. 5, Part II, No. 4). Loca-
tion.—The fused Jumbo-sacral section of the spinal column forms
the roof of the pelvic cavity.

Description.—The lumbo-sacral region consists of fourteen verte-

40 ANATOMY OF THE DOMESTIC FOWL

Fic. 11.—Bones from the scapular arch.

A. Dorsal vertebra. 1, Superior spinous ridge. z, Inferior spinous ridge. 3,
Oblique processes. 4, Intervertebral foramina. 5, Articular facette for head
of the rib. 6, Articular facette for tubercle of the rib. 7, Articular portion of
the body.

B. Outer surface of scapula.

C. Inner surface of scapula. 1, Thin caudal end. 2, Articular head. 4,
Processus furcularis. 5, Processus humeralis. 6, Processus coracoideus.

D. Outer surface of coracoid.

E. Inner surface of coracoid. 1, Thefurcular tuberosity. «, Articular facette
for articulation with the sternum. 3, Articular surface for humerus and scapula.

F, Outer surface of humerus and G the inner surface of the same. 1, Trochan-
teric fossa. 2, Oval articular head at proximal end. 3, Shaft. 4, Distal end
showing articular condyles. 5, Trochanter. 6, Trochleafor ulna. 7, Trochlea
‘for radius. 8, Depression or fossa.

H. Section through the median plane of the humerus showing the delicate
cross partitions illustrating provisions made for bones provided with air-sac
extensions,

OSTEOLOGY 4I

bre which are distinct in the body of the newly hatched chick, but
which become fused soon after hatching. With these vertebral
segments there are fused the last dorsal and first coccygeal vertebral
segments. This fusion is so complete that the segments are in-
dicated only by the intervertebral foramina on the sides through
which the spinal nerves pass, and by transverse markings on the
inferior surface of the bodies.

The lumbo-sacral vertebrz, called the sacrum, and the ilia are
fused. The dorsal spines of the vertebral segments are indicated
only in the anterior portion where they are fused, forming a plate.
There are no prominent ventral spines.

The Coccygeal Vertebre (Fig. 4, No. 27). Location.—The
coccygeal or caudal vertebra, or vertebrz coccygee, constitute the
bones of the tail.

Description—There are seven coccygeal vertebre. The last
segment, shaped like a plough share and therefore called thepygo-
style, is the largest and is supposed to have been formed by the
fusion of several original distinct segments. It supports the coc-
cygeal oil gland and the row of rudder feathers, or rectrices, which
are arranged fan-wise.

All of the coccygeal vertebrz except the first are freely movable,
thus allowing the tail to be used as a rudder during flight. The
lateral spines are long and well developed, and the superior
spines are bifurcated, thus giving increased surface for muscular
attachment. The first coccygeal segment is fused with the last
lumbo-sacral vertebra.

THE THORAX

The dorsal vertebra superiorly, the ribs laterally, and the sternum,
or breast-bone inferiorly, form the skeleton of a large cavity called
the thorax. The dorsal vertebra have been described.

The Ribs (Fig. 4, No. 32; Fig. 10, A and B). Location —The
ribs form the lateral bony wall of the thorax, articulating superiorly
with the dorsal vertebre.

Description.—The ribs are arranged in order of length, the ultimate
rib being the longest. From anterior to posterior, they approach
more nearly a horizontal position. The ribs are divided into the
true and the false. The true ribs articulate with the sternum. The
false ribs do not touch the sternum; they are floating. The true
ribs are composed of two parts, a vertebral, or dorsal, and a sternal,

42 ANATOMY OF THE DOMESTIC FOWL

or ventral. The vertebral part, or extremitas vertebralis, is provided
with an articular head, or caput coste; a neck, or collum coste;
and an articular tubercle, or tuberculum coste. The head and
tubercle articulate with the dorsal vertebra. Below the head of
each rib is a pneumatic foramen.

The distal extremity of the dorsal section of the rib articulates
with the proximal end of the sternal section by a diarthrodial
articulation.

The articulations of the true ribs with the sternum is diarthrodial
and each articulate by two small ridges with a double sternal facet.
The first, the second, and the seventh ribs are floating, or false
ribs. The first rib articulates with the quadrate part of the last
cervical vertebra and also with the first dorsal vertebra. ‘The
seventh, the last rib, articulates with the under side of the anterior
alar part of the ilium. This rib is situated similarly to the true ribs;
- but, instead of articulating directly with the sternum, the lower end
lies against the sternal segment of the rib just anterior to it.

From the posterior edge of the second, the third, the fourth, and
the fifth ribs, and near the middle of the dorsal segment, are flat,
uncinate, bony processes which project upward and backward, over-
lying in each case, the succeeding rib and giving greater surface for
muscular attachments and greater stability to the thorax.

The Sternum (Fig. 4, No. 40; Fig. 10, No. A,9). Location —The
sternum, or breast-bone forms the inferior portion, or floor of the
thoracic cavity.

Description —The sternum is a quadrilateral, curved plate with
processes projecting from each angle and from the middle of the
anterior and posterior borders. The posterior medial projection,
or metasternum, is the longest, and has a tall, plate-like ridge—
the sternal crest, crista sterni—running along its ventral surface.
The crest serves the important function of increasing the bony area
for the attachment of the powerful muscles which move the wings.
The anterior medial projection, or rostrum, is short, and pierced
at its root by an opening from which extend two elongated, saddle-
shaped depressions into which the end of the coracoid bones are
received.

The plate-like process of bone, the posterior lateral process, which
projects from the caudal angles of the sternum soon divides into two
parts. The shorter of these, the oblique process, broadens toward its
free end and covers the sternal segments of the last two ribs. The

OSTEOLOGY 43

sides of the sternum are thus provided with an external and an in-
ternal process forming an external and an internal notch. These
notches are bridged over by a broad ligament, to which the muscles
are attached. In poor flyers, as the domestic fowl, these notches
are large. The posterior end of the sternum is called the xiphoid
process or processus xiphoideus. Anteriorly the sternum is provided
with lateral external processes, the cotsal processes. The lateral
borders of the sternum are pitted by four depressions into which
the sternal segments of the ribs are received. The dorsal, or inner
surface of the bone is pierced by openings by which the air-sacs
communicate with the interior.

THE APPENDICULAR SKELETON

The appendicular skeleton consists of the shoulder girdle, the fore
limb, the pelvic girdle, or hip bone, and the hindlimb. The shoulder
girdle consists of the scapula, the coracoid, and-the clavicle. The fore
limb consists of the arm, forearm,.and the hand. The arm consists
of the humerus, the forearm of the radius and the ulna; and the hand
consists of the carpus, the metacarpus, and the phalanges. The
pelvic girdle consists of the ilium, the ischium, and the pubis. The
hind limb consists of the thigh, the leg, and the foot. The thigh
consists of the femur, and the leg consists of the tibia and the fibula.
The foot consists of the metatarsus and the phalanges.

THE SHOULDER GIRDLE

The shoulder girdle consists of the scapula, the clavicle and the
coracoid.

The Scapula. Location—The scapula (Fig. 11, A, B) lies on the
outer and superior rib surface, extending parallel with the dorsal
vertebre.

Description.—The scapula is a thin, sword-like bone, becoming
thicker as it approaches the shoulder-joint. The scapula expands
and becomes thin near the free end, which reaches nearly to the
antero-lateral portion of ‘the ilium (Fig. 4, No. 24). The scapula -
articulates with the coracoid. A pneumatic foramen is located at
the base of the acromion process. The anterior part of the scapula
is provided with an articular head and is provided with an inner
process, called the processus furcularis, which lies near the furcula
and coracoid. An outer stronger processus humeralis forms the

44 ANATOMY OF THE DOMESTIC FOWL

posterior half of the glenoid cavity, or cavitas glenoidalis, in which
the humerus articulates and the processus coracoideus.

The Clavicle. Locatton.—The clavicles, commonly known as the
wish bone, are located in the anterior chest region.

Description—The clavicles are long, slender bones uniting below
in the hypocledium, a laterally flattened process. They are joined
to the upper end of the coracoid by fibrous cartilage. The hypocle-
dium is joined to the anterior point of the sternum by the claviculo-
sternal ligament. The clavicles, as united by the hypocledium,
form a v-shaped structure called the furculum, or, popularly, the
wish bone.

The forks play the part of an elastic spring, whose office it is to
prevent the wings from coming toward each other during contraction
of the depressor muscles. The conformation of ‘this bone is, there-
fore, like the sternum, related to the extent and power of flight;
and for this reason it is that, in swift flyers, the two branches of the
furculum are thick, solid, widely separated, and curved like a U;
while in those that fly heavily and with difficulty, these branches are
thin and weak, and join at an acute angle. The latter formation
greatly diminishes its strength, and lessens, in a singular manner,
the reactionary power of the bony arch it represents.

The Coracoid. Location—The coracoid is located just back of
the.clavicle and at the side of the entrance of the thoracic cavity.
It is the strongest bone of the shoulder girdle, extending upward,
outward, and forward. It articulates inferiorly with the sternum
and, superiorly with the humerus and the scapula, and is attached
to the superior end of the furcular limb by a fibrous cartilage.

Description.—It is thinnest in the center or shaft and broadens
toward the inferior extremity. The upper hook-like part of the
coracoid forms the fore part of the glenoid cavity, and together with
the scapula and furcula form the foramen triosseum through which
passes the tendon of the elevator muscle of the wing. The upper
end flattens out into three tuberosities, the tuberositas furcularis
which is thick and to which attaches the limb of the furcula, the
tuberositas scapularis which unites to the scapula, and the tuberosi-
tas humeralis which lies between these and articulates with the

humerus.
THE FORE LIMB

The bones of the fore limb are humerus, ulna, radius, carpus,
metacarpus, and phalanges.

OSTEOLOGY 45

The Humerus. Location—The humerus constitutes the arm,
which, when at rest, lies parallel to the dorsal vertebra. It articu-
lates superiorly with the glenoid cavity. sa shallow ball-and-socket
joint, formed by the scapula and the’ coracoid; and inferiorly with
the ulna and radius. \seer

Description.—The proximal extremity of the humerus is provided
with a trochanter (Fig. 11, G, No. 5) and a large oval head or caput
humeri, which articulates in the glenoid cavity. The head is an
elongate, semi-oval convexity, with the long axis transverse from the
radial to the ulnar side and with the ends continued into upper and
lower crests. The upper crest of the head of the humerus is on the
radial side and the lower crest on the under side. Under this latter
crest there is a pneumatic fossa (Fig.11,F, No. 1), at the upper end of
which there is an opening into the bone, the pneumatic foramen,
which brings the air-sac into communication with the air space
of the bone. The shaft, or corpus humeris, is irregularly cylindrical
and slightly S-shaped.

The proximal part of the shaft, which is expanded on the
palmar side, is concave across and convex lengthwise. The dis-
tal part is slightly flattened. The shaft of the humerus is almost
cylindrical.

The distal extremity of the humerus is provided with two articu-
lar condyles, one of which articulates with the ulna and the other
with the radius. On the radial side of the palmar surface there is
a ridge; and on the ulnar side of the same surface there is a second
ridge diverging to the opposite tuberosity. The radial surface is
a narrow, subelongate convexity, extending from the middle, ap-
proximately, of the palmar surface, obliquely to the lower part of the
radial tuberosity. The two articular convexities, or trochlea, at the
distal end of the humerus are bent toward the palmar aspect, the
enconal aspect is the side on which the elbow is situated. The inner
convexity is the larger and articulates with the ulna. To the out-
side is the processus cubitalis humeri. The outer articulates with the
radius and is so arranged that the radius makes a greater flexion than
the ulna. At the lower end of the humerus there is a depression
which receives the anconeus of the ulna during flexion and extension
of the forearm. On the shoulder- and elbow-joint are found grooves
over which the tendons glide, at which places sheaths are provided.
This arrangement also aids in keeping the capsular ligament in
place.

46 ANATOMY OF THE DOMESTIC FOWL

The Ulna. Location.—The ulna, larger than the radius, is bent
and articulates with the radius only at the ends. The two bones
are bound together by a ligamentous band. It also articulates
superiorly with the distal end of the humerus, and inferiorly with
the carpus. When the wing is folded the radius is superior and a
trifle to the inner side of the ulna.

Description.—The proximal end is most expanded, and is obliquely
truncate for the articular excavation adapted to the ulnar tubercle
of the humerus. A short angular process behind the cavity repre-
sents the olecranon, which is the processus olecranalis coracoideus
ulne to which the ligamentum capsulare cubiti attaches. On the
inner side of the head is the internal tubercle of the ulna and on the
external side the external tubercle of the ulna. An excavation is
noted on the radial side of the proximal end for the lateral articula-
tion of the head of the radius. On the upper side near the articular
part is located the sigmoid cavity.

The shaft, or corpus ulnz, decreases in size near the distal end.
It is slightly curved, flattened laterally with an internal and an ex-

ternal ridge.

The distal end of _the ulna is slightly expanded into a ¢trochlea
which is sharply convex and articulates with two free carpal bones,
the scapho-lunar, or os carpi radiale, and the cuneiform, or os carpi
ulnare. The scapho-lunar is placed on the radial side, and the carpi-
ulnare on the ulnar side. The distal extremity of the ulna is pro-
vided with a styloid process and on the dorsal side with a tubercle.

The Radius. Location—The radius lies beside the ulna with
which it articulates at each extremity. At the inferior extremity the
articulation is rotary. It also articulates superiorly with the hu-
merus and inferiorly with the os carpi radiale.

Description.—The radius, cylindrical in shape, is more slender
than the ulna.

The proximal end is expanded, subelliptical, with a concavity
for the oblique tubercle and a thickened convex border for articu-
lation with the ulna. This end is provided with the tuberositas
radit.

The shaft, or corpus radii, is slender, subcompressed,. and has a.
slight bend upward from the ulna. A nutrient foramen occurs in
this shaft.

The distal end is expanded and rather flattened with two grooves
on the anconal side for passage of tendons. For articulation with

OSTEOLOGY 47

the scapho-lunar the radius is provided with a terminal transverse
convexity produced palmad, which also articulates with the ulna
laterally. There is a tuberosity on the radial side of the expansion
and inferiorly the inferior tuberculum ossis carpi radialis and supe-
riorly a superior tuberculum ossis carpi radialis.

The Hand.—The hand is made up of the carpus, the metacarpus,
and the phalanges.

The bones of the hand are so arranged as to allow abduction and
adduction, or flexion in the ulno-radial plane, movements which are
necessary in the outspreading and folding of the wing. Thus the
hand of the fowl moves in a state of pronation, without the power of
rotation. The carpal bones are so placed between the anterior arm
and metacarpus as to reduce the abduction which is necessary to
hold and extend the wing, so that the hand or wing be in a fixed
position.

The Carpus.—The carpus in the domestic fowl is represented by
two bones, ossa carpi, called the scapho-lunar, or os carpi radiale,
and the cuneiform, or os carpi ulnare. The scapho-lunar is the:
smaller and is located between the’ radius and metacarpus. The
cuneiform is the larger and is located between the ulna, the radius,
and the metacarpus. The cuneiform is somewhat anvil-like in
shape, being provided with a body and two prongs.

The Metacarpus.—The metacarpal bones, or ossa metacarpi,
two in number, are separated at their middle portion, and consoli-
dated at their extremities. ‘The upper proximal base of the meta-
carpus is provided with a tubercle, the tuberculum muscularis, and
externally the tuberculum ulnare ossis metacarpi. The distal end
of the metacarpal bone is provided with a tuberculum articulare.

The Phalanges.—The first three fingers only are represented, and
these are rudimentary.

The first finger called the pollex or thumb, consists of but one
joint. It is located on the proximal and outer end of the metacarpal
bone. It has on its proximal end a tubercle, the tuberculum
articulare.

The second finger, the best developed, consists of two phalanxes.
These are the main bones extending from the metacarpus. Each
articular end is provided with a tuberculum articulare.

The third finger, small, cylindrical in shape, is located at the
distal and inner side of the metacarpal bone.

48 ANATOMY OF THE DOMESTIC FOWL

THE PELVIC GIRDLE (Fig. 4, No. 25; Fig. 5, Part II, 6)

The pelvic girdle is made up of three bones as follows: the ilium,
the ischium, and the pubis, all of which are fused in adult life.
They are separate in the baby chick (Fig. 5, Part II, 6). The pelvis
together with the lumbo-sacral vertebre forms a thin, irregular,
shell-like structure extending superiorly from the tail to the thoracic
region. The sacrum is broad posteriorly and together with the
ilium forms the pelvic roof. The ilium and ischium are its lateral
walls.

The top surface of the pelvis shows the fovea ilio-lumbalis dorsalis,
which is bounded mesially by the crista ilii. Between it and the
spina lumbalis there is a broad furrow, the bottom of which is formed
by the dorsal surface of the lumbar vertebra. The sulcus ilio-
lumbalis dorsalis is formed by the rims of the ilia, so that a ridge is
observable. The cavum ilio-lumbale dorsale is formed by the iliac
rims on either side. Antceriorly is the canalis ilio-lumbalis, which is
formed by the ilium and the lumbar vertebral spines. It is located
longitudinally to the vertebre. - The anterior opening of this canal
is the larger. Posterior to the acetabulum is the post-acetabular
ridge.

The under part of the pelvis presents three distinct regions.
The cavity is divided into the fovea lumbalis, or anterior part,
the fovea ischiadica, or mesial part, and the fovea pudendalis, or
posterior part. Posterior to these is the region called the planum
coccygeum.

The fovea lumbalis contains the anterior lobe of the kidney,
and is circumscribed anteriorly by the last rib-carrying vertebra,
and posteriorly by the transverse process of the last lumbar
vertebra.

In the fovea ischiadica which follows, lie the nerve plexus
ischiadicus and the middle lobe of the kidney. Its posterior
boundary is the linea arcuata. The linea arcuata is a line drawn
from the acetabulum of the one side to the acetabulum of the other
side.

The fovea pudendalis contains the posterior lobe of the kidney.
The posterior boundary is the anterior border of the first coccygeal
vertebra. It gives passage to the nerve plexus pudendo-hemor-
rhoidalis.

The ilium, the ischium, and the pubis join to form the cotyloid

OSTEOLO GY 49

cavity, or acetabulum, in which articulates the head of the femur.
The floor of the cavity is perforated by a relatively large round
foramen.

The ium. Location.—The ilium, together with the lumbo-sacral
vertebra, forms the roof of the pelvic cavity. It articulates at its
inner border with the lumbo-sacral vertebre, postero-laterally with
the ischium and at the cotyloid cavity with the pubis.

_ Description—The ilium is remarkable for its development
‘in the long axis of the vertebral column. It is long and
narrow; and mesially, where it is thickest it forms the upper wall
of the acetabulum. Anterior to the acetabulum it is outwardly
concave, and posterior to the acetabulum it is convex. The ilium
fuses with the last dorsal vertebra and with the lumbo-sacral
vertebre and is excavated on its internal face. This surface is
irregular and lodges the kidneys. This inner margin of the renal
part enters with the square extensions of the posterior excavation
passing into the posterior iliac spine. The external margin is the
extension of the crista transversa and forms the processus ischiadicus.
Posteriorward the renal part of the ilium joins the ischium.

The ilia converge at the summits of the anterior sacral spines
forming the ilio-lumbar spines.

The ilium is joined to the square extensions of the last sacral
vertebra by the symphysis ilio-sacralis, to the larger part of the
lumbar vertebra by the sutura ilio-lumbalis, and to the transverse
processes of the last sacral vertebre by the symphysis ilio-sacri.

The Ischium. Location.—The ischium is located in the postero-
inferior part of the pelvis. It joins superiorly with the ilium, and
inferiorly with the pubis.

Description—The ischium is smaller than the ilium and is a
flattened, triangular-shaped bone, thickest where it forms the
posterior part of the acetabulum, becoming thinner and broader as
it extends backward. Posteriorly it forms the caudal extension.
The inferior border is turned slightly outward and is fused with the
pubis. Between these bones there is located the large oval ischiadic
foramen, through which passes the ischiadic nerve. This bone aids
the ilium in the formation of the obturator foramen through which
passes the tendon of the internal obturator muscle. The lower
part of the ischium which separates the ischiadic foramen from the
obturator foramen is called the ramus ascendens ossis ischii.

50 ANATOMY OF THE DOMESTIC FOWL

The Pubis. Location—The pubis is located along the inferior
margin of the ischium and extends further back than the posterior
border of the ischium.

Description—The pubis is a long, slender, rib-like bone. It
forms the lower and front portion of the acetabulum. The ischiadic
foramen formed by the ischium and pubis is single and nearly
circular in fowls, double in pigeons, and in geese and ducks it is
elongate.

THE HIND LIMB (Fig. 4, Nos. 35, 47, 48, 49, 50, 51, 52, and 53; Fig. 12)

The pelvic, or hind, limb supports the body. The bones of
each leg are the femur, which constitutes the thigh, the tibia and
the fibula, which represents the leg, and the metatarsus and the
phalanges, which form the foot.

The Femur (Fig. 12, A and B). Location—The femur, or os
femoris, the first bone of the hind extremity, extends obliquely
downward and forward, articulating with the acetabulum above
and the tibia, the fibula, and the patella below.

Description —The femur, one of the largest, thickest, and strongest
bones of the body, belongs to the class of cylindrical bones,
and presents for examination a shaft and two extremities.

The superior, or proximal extremity, is provided with a head,
caput femoris; the neck, collum femoris; and the trochanter. The
head is relatively small, and is marked by a depression above for the
round ligament which fills the cavity in the acetabular wall. Its
axis is nearly at right angles with the shaft. A neck joins it to the
body at the proximal end. External to the head of the femur is
the trochanter. The trochanter presents an outer convexity over
which the tendon of the gluteus maximus extends to become inserted
below. The érochanteric ridge, which is opposite the articular
head, presents an outer flattened surface which possesses impressions
for muscular attachments. The- trochanteric fossa, or fossa tro-
chanterica, is shallow.

The shaft, or corpus femoris, is shorter than the tibia, is in general
cylindrical, bent forward, and ‘the lower half is flattened and ex-
panded transversely. A nutrient foramen is located in the median
portion of the shaft. The shaft shows muscular linear ridges.

The distal extremity is large in both directions and comprises the
trochlea in front and two condyles behind, one internal and one ex-

OSTEOLOGY 51

ternal. The condyles are separated by the intercondyloid fossa, or
fossa intercondyloidea, which is marked with pits for the attachment
of ligaments; and above this is the epitrochlear fossa.

Fic. 12.—Bones of the hind extremity.

A. Posterior view of femur.

B. Anterior view. 1, Shaft. 2, Proximal extremity. 3, Distal extremity.
4, Articular head. 5, Trochanter major. 6, Shallow trochanteric fossa. 7,
Convexity over which the tendon of the gluteus maximus glides. 8, External
condyle. 9,Internalcondyle. 10, Nutrient foramen. 11, Intercondyloid fossa.
12, Muscular linear ridges. 13, Epitrochlear fossa.

C. Internal view of tibia. : ,

D. External view. 1, Shaft. 2, Articular head. 3, Distal end. 4, The
rotular process. 5, The fibular ridge. 6, External condyle: 7, Internal con-
dyle. 8, Intercondyloid space. 9, Nutrient foramen. at

E. Fibula, lateral view. 1, Articular head. 2, Its attenuated portion.

F. Posterior view of metatarsus. 1, Trochlea for inner or second digit. xz,
Trochlea for middle or third toe. 3, Trochlea for outer digit. 4, Bony core
for spur. 5, Bony canal for tendons. 6, Groove for tendons. 7, Fossa inter-
condyloidea.

The inner condyle begins anteriorly as a ridge, and expands into
a convexity which attains its greatest breadth posteriorly where it

52 ANATOMY OF THE DOMESTIC FOWL

becomes more flattened. The inner side of the inner condyle is
flattened and is provided with a tuberosity at its mid-part and a
second just above the posterior part of the condyle.

The outer condyle is formed in the same manner as the inner con-
dyle. It is indented at its broad, lower end by an angular groove,
which, winding divides the posterior part of the condyle into two
convexities. The more externa] ,convex ridge and the groove di-
viding it from the outer condyle are adapted to the head of the fibula.
There is in this part a fibular ridge and above this ridge a tuberosity.

The Tibia. Location.—The tibia (Fig. 12, D and C) extends ob-
liquely downward and backward from the knee-joint to the hock.
It articulates above with the femur and, by its procnemial process
with the patella, below with the metatarsus, and laterally with the
fibula.

Description.—The tibia is the longest bone in the posterior limb,
and possesses a shaft and two extremities. It is largest at the proxi-
mal end and presents three faces.

The proximal extremity presents a semi-oval articular surface,
not quite at right angles with the shaft, which articulates with the
condyles of the femur. The margin is raised toward the anterior
of the bone. The head of the tibia, or caput tibie, extends into a
rotular process which extends transversely, and is truncate. From
the anterior of this process there descends two vertical ridges; one
near the angle of the rotular process, the procnemial ridge; the cther
from the outer fibular angle, the ectocnemial ridge. On the outer side
of the intercondylar tuberosity there is a surface for the ligamentous
union with the head of the fibula; and a short distance below this
there is a vertical ridge for the close attachment, almost a fusion,
with the fibula, called the fibular ridge.

The shaft, or corpus tibie is straight and the upper two-thirds
subtrihedral; the lower third oval. A nutrient foramen occurs near
the upper postero-internal portion of the middle third of the
bone.

The distal extremity is much smaller than the proximal one;
it is quadrangular in form. The expanded inferior end of the tibia
forms two articular condyles above which posteriorly there is the
epicondyloid fossa. The inner condyle, the larger, has a groove near
the lower end of the anterior part of the shaft, which deepens to-
ward the intercondyloid space. This intercondyloid fossa in young
birds is covered by a strong ligament, which in older birds, becomes

OSTEOLOGY 53

ossified. On the lateral side of each condyle, there is a depression
for the attachment of ligaments.

The Patella. Location.—The patella, or knee-cap, thin and wide,
articulates with the procnemial process of the tibia, and with the
deep trochlea of the distal end of the femur.

Description —The patella is irregular in shape with three faces
and three borders. The posterior surface is articular. The other
two surfaces are rough for tendinous attachment. The patellar
ligaments in old birds may become ossified.

In order to turn the foot in and out, the tibia not only turns
around the inner condyle of the femur, but also around the patella,
so that the posterior surface turns outward and thus turns outward
the metatarsus and all the toes.

The Fibula. Location.—The fibula lies at the outer border of the
tibia. It articulates superiorly with the outer condyle of the femur,
and laterally with the tibia.

Description —The fibula is rudimentary; it is largest superiorly and
tapers toaslender point. The head is compressed laterally, and fur-
nishes an upper and an inner articular surface.

The Tarsus.—There exist, during fetal development of the chick,
two rows of tarsal bones which later become fused. The upper
row fuses with the tibia and the lower with the metatarsus. There-
fore, in the adult, there is no tarsus.

The Metatarsus. Location—The metatarsal bone extends down-
ward and forward. In birds it consists of one bone, which ar-
ticulates superiorly with the inferior extremity of the tibia. On the
‘distal end it has a threefold trochlear arrangement which articulates
with the three principal digits.

Description—The proximal extremity posteriorly has a process
which may be considered ds a consolidation of originally separate
metatarsal bones. The process at the supero-posterior part of
the metatarsus is called the hypotarsus of the tarso-metatarsus,
through which extends a canal called the hypotarsal canal, and which
‘gives passage to flexor tendons.

The proximal end of the metatarsus is ossified from one center of
ossification forming an epiphysis which caps the ends of the three
‘original metatarsal bones that coalesce, first with one another, then
with the epiphysis, thus forming a single compound bone. Above
and just to the inside of the metatarsus there may occur a small
bone which is imbedded in ligaments and articulates with the

54 ANATOMY OF THE DOMESTIC FOWL

inner proximal surface of the metatarsus. This has been called
by Gadow a sesamoid bone. .

The shaft shows tendonal grooves which are best marked on the
posterior surface. The shaft is rounded at the sides and flattened
on the anterior and posterior surfaces. At the juncture of the
middle and inferior thirds of the metatarsus there is a conical process
turned slightly backward, which serves as a base for the spur. The
spur is a horny structure.

At the distal extremity occurs the threefold trochlear arrangement
mentioned above, which incloses the fossa intercondyloidea. The
inner trochlea is the broadest, and the outer the narrowest. ‘The.
inner trochlea articulates with the proximal end of the second, the
middle with the third, and the outer with the fourth toe.

The Phalanges. Location—Most domestic fowls are provided
with four digits, or toes; the Houdan and Dorking are provided with
five. In fowls with four toes the three principal toes, the second, the
third, and the fourth, are directed forward, and the first, or hallux,
is directed backward.

Description—The last phalanx of each toe, called the ungual
phalanx, is slightly curved downward, is pointed anteriorly, like
the claw of the cat or dog, and is covered with a horny sheath. The
articular ends of the joints of the phalanges are enlarged. ‘The base
of the basal phalanx has two enlargements, the superior-inferior
tubercles, or tuberculum superius et inferius, between which is lo-
cated the fossa articularis transversa. Laterally the head has two
condyles, condyli laterales, which are divided by the sulcus longi-
‘tudinalis. ‘The bodies of the phalanges vary in form; they are supe-
riorly rounded, but inferiorly rounded, flat, or even somewhat con-
cave. The distal extremity has an articular trochlea. _

The first toe, or digit, called the great toe, or hallux, is composed
of three phalanges, or segments. The first segment, or basal
phalanx is considered a rudimentary metacarpal bone; it is at-
tached by a fibrous cartilaginous tissue to the inner posterior
surface of the inferior extremity of the metacarpal bone just be-
low the spur. ;

The second toe, likewise composed of three phalanges, is directed
forward. It articulates with the inner trochlea located on the

inferior metacarpal bone.
The third toe, made up of four phalanges, is the middle of the

OSTEOLOGY 55

three forward toes. It articulates with the middle trochlea of the
inferior extremity of the metacarpal bone.

Tfte fourth toe, is composed of five phalanges; it is, however,
of approximately the same length as the third, the segments being
shorter. The fourth or outer toe articulates with the outer trochlea
of the distal extremity of the metacarpal bone.

ARTHROLOGY

Kinds of Joints.—Joints may be movable, immovable, or mixed.
In movable, or true joints the articular surface of each bone is covered
by cartilage. The bones are held together by ligaments, the
capsular one often surrounding the joint and enclosing the synovial
membrane. In some joints there is a pad of fibrous cartilage
interposed between the two articular cartilages. Such a pad,
called a meniscus, adds to the elasticity and the free movement
of the joint. Movable joints form the mest numerous class; they
are for the most part found in the limbs.

In an immovable joint there is only a thin layer of fibrous or
cartilaginous material interposed between the bones. The fibrous
layer of the periosteum of both bones unite to cover the connecting
material and becomes attached to the same, thus serving as a liga-
ment. If the connecting material is fibrous, the joint is called a
suture; if cartilaginous, a synchondrosis. These joints are found
in the skull and in the pelvis.

The term mixed is used with reference, not to the motion in joints,
but to their structure, which partakes of the nature of both the
movable and immovable. The bones are firmly joined by a strong
interposed pad of fibrous cartilage to which also is adherent the
ligaments of the joint. There are no capsular ligaments; the
cartilaginous pad or disc is softer toward its center, where occasion-
ally there may be one, or even two, narrow cavities. Authorities
differ as to whether such cavities are lined by synovial membrane
or not. Since there are really no frictional surfaces in such a joint,
motion depends upon the flexibility of the disc. The joints between
the vertebral centra afford the best illustration of the mixed class.

Movement of Joints.—The movements admissible in joints may
be divided into four kinds: gliding, angular movement, circumduc-
tion, and rotation. These movements are often, however, more or
less combined in the various joints. It is seldom that there occurs
only one kind of motion in any particular joint.

Gliding movement is the most simple kind of motion that can

56

ARTHROLOGY 57

take place in a-joint, one surface gliding or moving over another
without any angular or rotary movement.

Angular movement occurs only between the long bones. By
it the angle between the two bones is increased or diminished. It
may take place in four directions: forward and backward, consisting
of flexion and extension; or inward and outward from the medial
line of the body, consisting of adduction and abduction. Abduction
of a limb is movement away from the medial line of the body.
Adduction of a limb is movement toward the medial line of the body.

Circumduction is that limited degree of motion which takes
place between the head of a bone and its articular cavity, whilst
the extremity and sides of the limb are made to circumscribe a
conical space, the base of which corresponds with the inferior
extremity of the limb, the apex with the articular cavity; this
kind of motion is best seen in the shoulder- and hip-joint.

Rotation is the movement of a bone upon an axis, which is the
axis of the pivot on which the bone turns, as in the articulation
between the atlas and axis, when the odontoid process serves as a
pivot around which the atlas turns; or else is the axis of a pivot-
like process which turns within a ring, as in the rotation of the radius
upon the humerus.

Pronation is a form of rotation in which the inferior extremity
of the radius passes before the ulna, and thus causes the hand to
execute a kind of rotation from without inward.

Supination is a form of rotation in which the movement of the
forearm and hand are carried outward so that the anterior surface
of the latter becomes superior. .

The Ligamentous Structure.—Ligaments are dense, fibrous, con-
necting structures. They are made up principally of white fibrous
tissue and exist in all true joints.

There are four kinds of ligaments associated with true joints:

The first kind, the capsular ligament which encloses all true
joints, is thin and consists of interlaced fibers attached to the bone
at the edges of the articular cartilages. It either partly « or wholly
surrounds the joint, enclosing and protecting a synovial apparatus,
which, by secreting a liquid resembling serum, lubricates the joint
to prevent friction.

The second kind, the binding or .lateral ligaments, consist of
flattened or rounded cords or bands of fibrous tissue. Such a
ligament extends from one bone to the other, and firmly attached to

58 ANATOMY OF THE DOMESTIC FOWL

their roughened surfaces, holds the bones in place and at the same
time allows the required amount of motion.

The third kind, located between the joints, is called interosseous
ligament.

The fourth kind, called the annular ligament binds down and
protects the tendons. :

Ligaments of the Ear'.—The concha of the ear is provided with
a superior and an inferior ligament.

Ligaments of the Jaw.—The articulations of the lower jaw are
complex. The freely movable articulation is between the inferior
maxilla and the quadrate. Less freely movable articulations are
formed by the quadrate with the temporal, the zygomatic and the
pterygoid. A lateral ligament of the jaw, the articulojugale ex-
tends from the posterior border of the inner wing of the os articulare
of the inferior maxilla (Fig. 8, No. 1c, and Fig. 19, No. 15) to the
outer border of the os quadrato jugulare.

A lateral temporo-maxillary ligament extends from the outer sur-
face of the temporal bone to the outer border of the os articulare
of the inferior maxilla (Fig. 8, No. 11, and Fig. 19, No. 14). |

Ligaments of the Vertebree.—In each space between the bodies
of the vertebre there is a meniscus intervertebralis. This meniscus
is analogous to the annulus fibrosus of mammals (Gadow), which,
is possibly formed as a protrusion of the anterior surface of the ver-
tebral body. The meniscus or disc may develop into a ring-shaped
structure, the true meniscus, or it may develop to different degrees
as an extension of the vertebral body surface, and become, as in the
dorsal and lumbar regions, fused with the vertebral segments, in
which case it is called the annulus fibrosus.

The vertebral disc which is connected with the atlas and which
is fused with that bone, represents the first meniscus, which is called
the ligamentum transversum atlantis. This, as well as other ligaments
of the spinal column, may become ossified.

The ligament which is located between those vertebral bodies
which face each other and is inside the joint cavity, is called the
ligamentum suspensroium corporum vertebralium. It passes through
the central opening of the meniscus and lies exactly in the long axis
of the body of the vertebra.

The first ligament of the neck is the ligamentum suspensorium
dentis epistrophet. The ligamentum capsulare atlantico-occipitale

1 The classification of Gadow is used.

ARTHROLOGY 59

and the ligamentum capsulare atlantico-epistrophicum odontoideum
are two parts of the joint capsule of the vertebral body. Other
ligaments of this part are the membrane obturatorie intervertebrales
posteriores, which are located between the semicircular rims of the
neck vertebre.

The ligamentum transversum atlantis surrounds the occipital
condyle.

The ligamentum nuche is a thin, membranous, ribbon-like struc-
ture which lies between the muscles of the right and those of the
left side of the middle, and the lower part on the posterior of the neck,
and ends in attachments to the superior spines of the cervical
vertebre.

The ligamentum elasticum interspinale profundum and the liga-
mentum elasticum interspinale superficiale and the three last named
are the ligaments which keep the neck of the fowl in the PanaDS
without the action of the muscles.

The ligamentum capsulare obliguum connects the facets of the
oblique processes.

Ligaments of the Ribs.—The thick inferior end of the sternal por-
tion of the true rib has two small articular heads, which articulate
with two depressions in the articular surface of the sternum. This
articulation is held firm by a capsular ligament.

The upper end of the sternal rib forms an almost perfect right angle
with the inferior end of the dorsal rib with which it is connected by a
joint provided with a synovial apparatus and a capsular ligament.
This arrangement allows free movement outward and inward and is
the main joint in respiration.

The upper end of the dorsal portion of the rib articulates with the
dorsal vertebra. The joint formed by the articular head with the
body of the vertebra is provided with a capsular ligament. The
tubercle of the rib articulates with the facet on the transverse proc-
ess of the dorsal vertebra, and is provided with a transverse liga-
ment, called the ligamentum transversum externum. It is also pro-
vided with a capsular ligament.

The ligamentum triangulare connects each processus uncinatus
with the succeeding rib. This ligament is in the form of a membra-
nous sheet, or aponeurosis.

Ligaments of the Sternum (Fig. 13).—The external and’ the in-
ternal notches of the sternum are bridged over with a thin membrane

60 ANATOMY OF THE DOMESTIC FOWL

which gives an extensive surface for muscular attachments. The
sternal muscles overlie this portion.

‘

Boe a

Fic. 13.—Muscles of the fore extremity. Inside view. 1, Lateral external
process of sternum. 2, Lateral internal process of same. 3, Ligament of the
external notch. 4, Ligament of the internal notch. 5, Pectoralis major. 5a,
Its fan-shaped expansion at shoulder-joint laid back. 6, Pectoralis tertius. 7,
The coracoid. 8, Biceps. 8¢,Itslong head. 8b, Itsshort head. 09, Pectoralis
secundus. 10, Rectus abdominis. 311, Teres et infraspinatus. 12, Deltoid.
13, Capsular ligament. 14, Teres minor. 15, Coraco-brachialis. 16, Serratus
magnus anticus. 17, Extensor metacarpi radialis longior. 18, Pronator brevis.
19, Flexor carpiulnaris. 20, Flexor carpi ulnaris brevior. 21, Flexor digitorum
profundus. 22, Extensor indicis longus. 23, Extensor ossis metacarpi pollicis.
24, Humerus. 25, Shoulder. 26, Elbow. 27, Carpus. 28, Section through
vertebra. 29, Keel of sternum. 28a, Flexor brevis pollicis. 29a, Extensor
proprius pollicis. 30, Flexor minimi digiti brevis. 31, Interosseous palmaris.
32, Interosseous palmaris.

The sternum is connected by a fibrous mass with the inferior
portion of the clavicle, or hypocledium (Fig. 57), the claviculosternal
ligament.

The inferior narrow elongated end of the coracoid forms with the
sternum a true articulation, which is provided with a capsular

ARTHROLOGY 61

ligament, the ligamentum capsulare. Capsular ligaments occur at
the articulations between the sternum and ribs.

Ligaments of the Shoulder-joint (Fig. 13)—The shoulder-joint
is made up of the scapula, the humerus, and the coracoid. The ends
of these three bones form the foramen triosseum (Fig. 15, No. A, 7)-
through which passes the tendon of the elevator muscle of the wing.

The furcula, independent of the shoulder-joint or girdle, is attached
to the supero-internal part of the proximal end of the coracoid by
fibrous connective tissue; it is also connected to. the other bones of
the shoulder-joint by the ligamentum coraco-furculare and the
ligamentum. furculo-scapulare.

The ligamentum coraco-scapulare extends from the tuberosity of
the furcula to the coracoid and to the processus furcularis of the
scapula.

The ligamentum coracoido-scapulare externum extends between
the external tuberosity of the coracoid, the tuberosity of the scapula,
and the humerus. ;

The ligamentum coracoideo-scapulare inferius extends from the
coracoid to the inner tubercle of the scapula.

Another long, broad ligament belongs to the episternal apparatus.

The shoulder-joint is provided. with a wide, loose, capsular liga-
ment (Fig. 13, No. 13). Attached to the humerus are four other
ligaments, of which three pass from the anterior end of the coracoid
and the fourth from the scapula. The latter are as follows: first, the
supero-anierior ligamentum humero-coracoideum, which extends from
the small tubercle of the humerus to the coracoid bone; second, the
antero-inferior ligamentum humero-coracoideum, which extends from
the humerus to the coracoid, third, the ligamentum coraco-humerale,
which extends from the coracoid to the large tubercle of the humerus;
fourth, the ligamentum humero-scapulare which extends between the
processus humeralis of the scapula and the head of the humerus.

Ligaments of the Elbow-joint (Fig. 14).—The elbow-joint is made
up of the ulna, radius and the humerus. The ligaments of the elbow-
joint are as follows: the ligamentum capsulare cubiti, or capsular
ligament, which extends from the processus cubitalis of the humerus
to the processus olecranalis coracoideus of the ulna and to the tuber-
ositas radii of the radius (Fig. 15, No 5).

The ligamentum laterale cubiti externum connects the outer hu-
meral distal extremity with the head of the radius (Fig. 15, No. 2).

The ligamentum laterale cubiti internum lies between the inner

62 ANATOMY OF THE DOMESTIC FOWL

distal extremity of the humerus and the tuberculum internum of
the ulna (Fig. 14, No. 9).

The ligamentum annulare radii originates on the olecranon, sur-
rounds the head of the radius, and is attached to the tuberculum
internum of the ulna (Fig. 13, No. 3). _

The ligamentum cubiti teres extends from the head of the radius
to the upper end of the ulna (Fig. 15, No. 4).

Fic. 14.—Muscles and ligaments of the arm and forearm of a hen.

A. External view. 1, Expansor secundarium. z, Tensor patagii longus. 3,
Tensor patagii brevis. 5, Brachialis anticus. 6, Pronatorlongus. 7, Supinator
brevis. 8, Extensor indicis brevis. 10, Scapulo-humeralis.

B. Internal view. 9, Ligamentum laterale cubiti internum.

The ligamentum transversum spreads out between the head of the
ulna and the radius, thus uniting the two bones, and limiting supina-
tion (Fig. 15, No. 1).

Ligaments of the Carpal Joint.—The carpal joint is made up of
the ulna, radius, the two carpal bones and the metacarpus.

There are two strong ligamenta obliqua carpi ulnaris which ex-

ARTHROLOGY 63

tend from the processus styloideus of the ulna to the tuberculum
posterius carpi ulnaris of the os carpi ulnaris.

The ligamentum posticum ulnare carpi ulnaris extends from the
processus styloideus of the ulna to the os carpi ulnaris.

Fic. 1 5.—Ligaments of the arm and forearm of a hen.

A. The scapulo-coraco-humeral articulation. 1, Proximal end of the humerus.
2, Articular head of humerus. 3, Thecoracoid. 4, Proximal end of the clavicle.
5, Tendon of pectoralis tertius. 6, Tendon of pectoralis secundus. 7, Opening
or foramen triossium through which the tendon of the elevator of the wing
passes. (Pectoralis secundus. 8, Broken end of scapula.

B. 1, Ligamentum transversum. 2, Ligamentum laterale cubiti externum.
3. Ligamentum annulare radii. 4, Ligamentum cubiti teres. 5, A portion of
the ligamentum capsulare cubiti. 6, Distal extremity of humerus. 7, Ulna.
8, Radius.

C. Muscles of the outside surface of the arm. 1, Tensor patagii longus. 2,
Extensor digitorum communis. 3, Tensor patagii brevis. 4, Anconeus. 5,
Flexor carpiulnaris. 6, Biceps. 7, Triceps. 8. Deltoid. 9, Brachialis anticus.
to, Flexor metacarpi radialis. 311, Extensor ossis metacarpi pollicis. 12, Ex-
tensor metacarpi radialis longior. 13, Extensor indicis longus.

The ligamentum ulnare carpi radialis is a short ribbon-like ligament
which passes over the above-mentioned ligaments and is attached
to the inner surface of the os carpus radialis.

The ligamentum ulnare carpi radialis internum is a strong ligament

64 ANATOMY OF THE DOMESTIC FOWL

which originates on the inner part of the elbow. It extends to the
upper rim of the base of the main digit.

The ligamentum radiale carpi radialis externum originates on the
outside of the head of the middle digit and inserts to the superior
tuberculum carpi radialis of the radius.

The ligamentum carpi radialis internum, a short ligament, extends
from the inside of the head of the main digit to the inner rim of the
carpi radialis.

The ligamentum carpi interosseum is located between the carpal
bones.

The ligamentum ulnare metacarpi internum is spread out between
the processus styloideus of the ulna and the tuberositas muscularis
on the upper side of the middle finger base at a point where the
second and the third metacarpi separate.

The ligamentum ulnare metacarpi externum extends from the
tubercle of the distal extremity of the ulna, on the dorsal side,
to the tubercle on the base of the metacarpus.

Ligamentum radiale metacarpi extends from the head of the inner’
digit to a point near the tuberculum muscularis of the radius.

The ligamentum transversum ossis carpi radialis et metacarpi is
located between the inferior tuberculum ossis carpi radialis and the
first metacarpal bone. g

There is another ligament between the tuberculum superiorus
carpi radialis and the first metacarpal bone.

The ligamentum ossis carpi radialis internum et metacarpi extends
from the inner surface of the carpus radialis to the tuberositas mus-
cularis of the radius.

The ligamentum ossis carpi ulnaris externum et metacarpi extends
from the ulnar carpal bone to the tuberculum of the metacarpal bone.

The ligamentum ossis carpi ulnaris internum et metacarpi extends
from the processus uncinatus of the ulnar carpal bone to the tuber-
ositas muscularis of the metacarpal bone.

Ligaments of the Finger.—The ligamentum pollicare connects the
thumb with the first metacarpal bone.

The ligamentum anterius ossis metacarpi et prime phalangis
digiti secundi extends from the tuberculum articulare metacarpi, of
the proximal end of the metacarpus, to the tuberculum articulare of
the first phalanx of the second or large finger. Similarly attached,
are also an internal and a posterior ligament, or ligamentum internum
and ligamentum posterius.

ARTHROLOGY 65

The three phalanges are all provided with capsular ligaments, or
ligamenta capsularia, which bind together the several phalanges.

The small or third finger is connected to the metacarpus by a
capsular ligament, the ligamentum capsulare, and by an interosseous
ligament, or ligamentum interosseum digitorum, to the first phalanx
of the second finger.

Ligaments of the Pelvis——The obturator foramen, formed by the
ilium and the ischium, is covered by a broad membranous ligament
(Fig. 4, No. 20).

The oblong foramen, or foramen oblongum, and the foramen
ischiadicum, formed by the ischium and the pubis are covered by
broad membranous ligaments (Fig. 4, Nos. 29 and 60).

Poupart’s ligament or ligamentum Poupartii, quite small in fowls,
extends from the anterior lower rim of the ilium to the pelvic cavity,
and is inserted at the bottom of the acetabulum.

Another broad ligament originates from the posterior rim of the
ischium and is attached to the square surface of the first coccygeal
vertebra.

The ilio-pubic ligament extends from the pubic spine to the last
rudimentary rib.

Ligaments of the Hip-joint (Fig. 25, F).—The hip-joint is made up
of the ilium, ischium, pubis and femur and is a deep ball-and-socket
joint. The cavity or acetabulum is called a cotyloid cavity.

The hip-joint is provided with three ligaments.

The ligamentum capsulare femoris is attached around the rim of
the cotyloid cavity and around the rim of the articular head of the
femur (Fig. 25, No. F, 4).

The ligamentum teres, or round ligament, is a very short ligament
which closes the hole at the floor of the cotyloid cavity, at which
point it is attached. It is also attached to the head of the
femur.

The ligamentum ilio-sacrale strengthens the hip-joint capsule.
It passes from the lower anterior rim of the os ilii, extending over the
capsule to the neck of the femur to which it is attached.

The Ligaments of the Knee-joint (Figs. 16 and 17).—The
knee-joint is made up of the femur, patella, tibia and fibula, and
is provided with the following ligaments:

The ligamentum extero-laterale genu is a strong ligament extending
from the condylus externus femoris, or external femoral condyle
to the outer surface of the head of the fibula, or capitulum fibule.

5

ANATOMY OF THE DOMESTIC FOWL

66

t to a point

From this head there passes inward, a strong ligamen
between the femur and fibula (Fig. 25, No. D, 4).

The ligamentum intero-laterale genu extends from the outer

internus

ibia, or condylus i

surface of the internal condvle of the t

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It gives off a thin ligamentous slip which enters the joint
and is attached to the inner half-moon shaped pad of fibrous

tibie.

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the knee (Fig. 16, No. B, 2).'

cartilage

ARTHROLOGY 67

The ligamentum popliteum arises from the fossa poplitea of the
distal extremity of the femur and extends downward to the posterior
tim of the head of the tibia.

The anterior ligamentum cruciatum genu originates from the fossa
poplitea and extends outward antero-laterally to the rim of the
head of the tibia (Fig. 25, No. 6).

The posterior ligamentum cruciatum genu is a short, strong liga-
ment which originates from the-cavity of the internal condyle
of the femur, or condylus internus femoris, and inserts into the
internal glenoid cavity of the tibia (Fig. 25, No. 1) or cavitas gle-
noidalis interna. 2

The meniscus of thé*femoro-tibial articulation is divided into
four parts, as follows: first, the. internal adhesio cornu antici carti-
laginis lunate; second, the posterior adhesio cornu.antici cartilaginis
lunate; third, the external cornu cartilaginis lunate; fourth, the
anterior cornu antici cartilaginis lunate. The latter originates
between the condyles and passes around the ligamentum cruciatum
genu posticum (Fig. 16, No. B, 7).

The inner semi-lunar fibrous cartilage is well developed and is
joined by two ligaments between the femoral and the tibial surfaces
(Fig. 25, No. 1).

The external semi-lunar cartilage lies in a cavity between the
external femoral condyle and the head of the fibula (Fig. 25, No. 2).

The fibrous cartilages are bound posteriorly by a. ligament,
and by a second ligament to the head of the fibula, or capitulum
fibule. Both pads of fibrous cartilage are connected by a transverse
ligament called the ligamentum transversale commune (Fig. 25, No. 5).

The patella is provided with several ligaments, as follows:

The anterior patellar ligament, broad, strong, and irregular in
‘thickness, extends from the inferior margin of the patella to the
rim of the second tibial crest (Fig. 16, No. B, 3).

Internal ligamentum laterale genu. 3, Anterior patellarligament. 4, Patella.
5, Distal end of femur. 6, Proximal end of tibia. 7, Location of meniscus or
pad of fibrocartilage.

C. Anterior view of tibio-tarsal articulation. 1, Distal end of tibia. 2, Its
articular surface. 3, Ligamentum anticum. 4, Proximal end of metacarpus:
6, Pad of fibro-cartilage.

D. The dorsal surface of the coccyx. 1, The bilobate oil gland. 2, Its duct.
3, Levator coccygis.

E. Inside view of pelvis and thigh. 1, Obturator internus. 2, Ambiens. 3,
Vastus internus. 4, Internal ligamentum laterale genu. 5, Tibialis anticus.
6, Loop through which the tibialis anticus passes. 7, Adductors of the thigh.
8, Loop for the extensor tendon.

68 ANATOMY OF THE DOMESTIC FOWL

The ligamentum capsulare capituli fibule is spread out between
the head of the fibula, or capitulum fibule, and the superficies
glenoidalis peronea tibiz.

Fic. 17.—Muscles and tendons of the head and posterior extremity.

A. Section of neck with superficial muscles removed. 1, Obliquo-transver-
sales. 2, Interspinales. 3, Intertransversales. 4, Interarticulares.

B. Head showing muscles. 1, Beak. 2, Nostril. 3, Tongue. 4, Sublingual
salivary gland. 5, Pterygoideus. 6, Stylo-hyoideus. 7, Temporal. 8, Flexor
capitis inferior. 9, Rectus capitis lateralis. 10, Rectus capitis posticus major..
Iz, Trachelo-mastoideus. 12, Eye. 13, Mylo-hyoideus. 14, Genio-hyoideus.
15, Biventer maxilla. 16, Digastricus. 17, Rectus capitis anterior minor.

C. Foot of hen showing tendons. 1, Flexor perforans digitorum profundus.
2, Flexor perforatus medius primus pedis. 3, Sheath at joint through which
tendon passes. 4, Flexor perforatus indicis primus pedis. 5, Flexor perforatus
medius secundus pedis. 6, Flexor perforatus annularis primus pedis. 7, Flexor
longus hallucis.

D. Outside view of leg of hen. 1, Biceps flexor cruris. 2, Semitendinosus.
“3, Loop through which biceps flexor cruris passes. 4, Tibialis anticus. 5,
Flexor perforatus indicis secundus pedis. 6, Flexor perforatus medius primus
pedis. 7, Gastrocnemius. 8, Flexor perforatus annularis primus pedis. 9,
Flexor perfcratus medius secundus pedis. 10, Extensor longus hallucis.

The ligamentum tibio-fibulare extends from the head of the fibula,
or capitulum fibule, to the inner surface of the external crest,
or crista externa tibie, of the tibia (Fig. 25, No. 3).

ARTHROLOGY - 69

The ligamentum interosseum is a delicate ligament located between -
the tibia and fibula (Fig. 25, No. 4) which very early becomes
ossified.

Ligaments of the Tibio-metatarsal Joint (Fig. 16)—The tibio-
tarsal joint is made up of the tibia and metatarsus.

The ligamentum capsulare ossis tibio-metatarsi connects the tibia
and the metatarsus and surrounds the joint (Fig..16, Nos. A, 7 and
C, 7

The ligamentum extéernum, a long strong ligament, originates on.
the upper and outer surface of the external condyle, or condylus
externus of the tibia and is attached to the upper rim of the os
metatarsi (Fig. 23, No. 15).

The ligamentum anticum is spread out between the fossa inter-
condyloidea of the tibia and the tuberculum ossis metatarsi of the
proximal end of the metatarsus (Fig. 16, No. C, 3). Just posterior
to this ligament, there is an interosseous ligament, the ligamentum
interosseum.

A semilunar pad of fibrous cartilage, the cartilago semilunaris
is located between the. outer distal extremity of the tibia and upper
articular surface of the metatarsus (Fig. 16, No.C, 6). Its concave
portion is directed anteriorly and receives an insertion from the
ligamentum externum, or external ligament.

The tendon Achillis (Fig. 16, No. A, 1) may become ossified.

Ligaments of the Toes (Fig. 16).—In addition to the capsular
ligaments, which all true joints have, we find the following in con-
nection with the toes:

The ligamentum superius and the ligamentum inferius connect
the second toe with the great toe, or hallux.

The ligamentum laterale externum and the ligamentum laterale
internum unite the bases of the second, third and fourth toes to
the lateral faces of the trochleas of the inferior extremity of the
metatarsus.

The bases of the toes are held together by the ligamenta transversa.
All the rest of the toes are held together by the ligamenta capsularia
digitorum pedis and by two lateral ligaments, namely: the ligamentum
laterale externum and the ligamentum laterale internum.

MYOLOGY

Kinds and Structure of Muscles.—Muscles are highly specialized
structures which have the property of contractility when stimulated,
and thus produce motion. Muscular tissue is sometimes called
flesh. Two kinds of muscles are recognized; muscles of locomotion
and visceral muscles.

The muscles of locomotion may be in masses of different shape
attached to the skin, the dermal, or to the skin and skeletal structure,
the dérmo-osseous, or from one bone to another, the skeletal. The
visceral muscles form sheets and make up a portion of the wall of
many of the hollow organs, such as the intestines, the stomach,
the gizzard, the esophagus, and the blood-vessels. A special type
of muscle forms the heart.

When classified with reference to structure, muscular tissue
is divided into three types, as follows: voluntary-striated, in-
voluntary, and involuntary-striated. The microscopic examination
of each of these types of muscle shows it to be made up of fibers,
these fibers to be made up of muscle cells, the muscle cell to be in-
closed in a delicate tubular sheath, or membrane, called the sarco-
lemma. This membrane, tough and elastic, isolates each fiber.
The bundles of fibers, called fasciculi, are surrounded by a fibrous
sheath, which is called the perimysium internum; and the entire
muscle has likewise an investing sheath of connective tissue, called
the perimysium externum. ‘The muscular cells show a longitudinal
striation marking the fibrille, and they also show a cross striation.
Nuclei are found just beneath the covering, or sarcolemma, in the
striated muscle cell (Fig. 77, No. 2). In the involuntary and in the
involuntary-striated muscle cell, the nuclei are centrally located.

The voluntary-striated muscles consist of cylindrical fibers and with
a few exceptions, are under the control of the will. A muscle of
this type, the regular skeletal form, usually has at each extremity a
fibrous structure, called a tendon, by means of which it is attached
to the bones. The intermediate fleshy portion of the muscle, in
case of considerable bulk, is called the belly of the muscle.

The involuntary, non-striated, or smooth muscle, celis are spindle-
shaped, long, and pale in color (Fig. 77, No. 1). The cells lie end to
end forming fibers. These fibers do not terminate in tendons, but

79

MYOLOGY 71

are arranged in sheets and aid in forming the walls of the digestive
tract, to which they give the power of contraction and expansion.

Involuntary-striated, or heart muscle (Fig. 77, No. 4), occupies
an intermediate position between the two muscles just described.
It is composed of cells which branch, are somewhat rectangular.
They possess both longitudinal and transverse striation. Among
the fibers is found a small amount of connective tissue, as in the
former types of muscle, which gives support to the blood-vessels
and nerves.

Fascia.—The term fascia is applied to membranous expansions,
differing materially in strength, texture, and relations. Fascia is
composed of loosely arranged white fibrous connective tissue. At
least two layers may usually be distinguished, the superficial fascia
and the deep fascia.

Below the skin is the superficial fascia, which forms a continuous
covering over the whole body and serves to attach the skin to the
underlying structure.

The deep fascia more densely constructed, may be attached to
the skeleton, ligaments, and tendons.

When the fascia spreads out, becomes denser, and acts as a con-
tinuation of a mucle, it is called an aponeurosis.

The Muscular Nomenclature.—In the fowl there are 162 muscles,
single or in pairs. These muscles are named from their location,
as the lingualis; others from their attachments, as the dermo-tem-
poralis; some from their form, as the rhomboideus; others from their
use, as the flexor or extensor; and still others from their direction,
as the transversus.

THE DERMAL MUSCLES

Birds are provided with a system of delicate muscles divided into
numerous fasciculi, which harmoniously act upon the feather quills
and collectively agitate the plumage. These are the dermal muscles.
This group is divided into two subgroups: the true dermal muscles,
that is, those that have their origin and insertion to the under sur-
face of the skin; and the dermo-osseous, those that originate on the
surface of some bone and insert to the inner surface of the skin.

TRUE DERMAL MUSCLES

Dermo-frontalis _ Dermo-dorsalis
Dermo-tensor patagii Dermo-humeralis
Dermo-pectoralis

72 ANATOMY OF THE DOMESTIC FOWL

Dermo-frontalis.1_ Location —This muscle is somewhat rudimen-
tary and may be entirely absent. It is located in the frontal region
arid is about 2 or 3 centimeters long and not so wide.

Origin and Insertion.—Closely attached to the skin.

Shape.—Flat and rather rectangular.

Relations.—Superiorly with the skin and inferiorly with the frontal
bones.

Action.—By contraction the feathers on the top of the head lie
flat. Those above the eyes are elevated.

Dermo-dorsalis. Location In the median line of the neck and
back.

Origin and Insertion—Adhering closely to the skin, it generally
becomes lost at the occiput; it is most highly developed in the
mid-cervical region, and it gradually disappears over the caudal
region.

Shape.—Delicate and ribbon-shaped.

Relations —Superiorly it is attached to the skin. Fat sometimes
surrounds the muscle.

Action —By contraction it raises the feathers along the superior
part of the neck and dorsal region.

Dermo-tensor Patagii. Location—Between the root of the neck
and top of the shoulder.

Origin and Insertion—Attached to the skin in the region of the
anterior part of the root of the neck, some fibers passing obliquely
upward and blend with fibers of the dermo-temporalis. It blends,
by a slender tendon, with that of the tensor patagii longus.

Shape.—A bundle of muscular fibers later becomes thin, delicate,
and triangular in shape.

Relations.—Externally to the skin.

Action.—Auxiliary to the tensor patagii longus. A tensor of
this region.

The patagii are associated with the wing fold of skin which fills
the angle between the arm and forearm. This fold contains elastic
tissue and muscle.

Dermo-humeralis. Location.—Lateral thoracic region.

Origin and Insertion.—Fan-like delicate fibers from the skin in
the abdominal integument, contracting into a long narrow fasci-
culus of fibers, again spreading out in fan-shape to be inserted to the
tendon of the pectoralis major, just below its insertion.

1The classification of Shufeldt is used.

MYOLOGY 73

Shape.—Triangular, fan-shape.

Relations —Superiorly with the skin.

Action.—Controls the skin in this region. The anterior end being
fixed, the muscles are raised; and the posterior end acting as the
fixed point, the feathers are caused to lie close to the body.

Dermo-pectoralis. Location.—On each side of the chest, lying
in a longitudinal manner.

Origin and Insertion—Attached to the skin on either side of the
thorax corresponding to the dermo-dorsalis. Anteriorly it disap-
pears over the region of the origin of the cleido-trachealis, and pos-
teriorly just behind the tips of the postpubic parts of the pelvis.

Shape.—Thin, delicate.

Relations.—Superiorly with the skin.

Action—The anterior part acting as the fixed point, the feathers
of the chest are raised; and the posterior end acting as the fixed
point, the feathers are made to lie flat.

THE DERMO-OSSEOUS MUSCLES

Dermo-temporalis Platysma myoides
Dermo-cleido dorsalis Cleido-trachealis
Dermo-spinalis Dermo-iliacus

Dermo-ulnaris

Dermo-temporalis (Fig. 18, No. 1). Location From the tempo-
ral region down the side of the neck to the anterior part of the
thoracic region.

Origin.—By a broad tendinous attachment from a small depres-
sion above and anterior to the temporal fossa. From here the
fibers pass upward and backward and then downward.

Insertion —A few fibers blend with those of the cleido-trachealis.
The fibers are then lost upon the skin in front and opposite the
shoulder-joint. Some of the fibers blend with those of the dermo-
tensor patagii.

Shape.—Long, flat, and ribbon-shaped. The lower portion con-
sists of delicate fibers.

Relations-—Superior to the temporal muscle and sphenotic
process. Superior to the cleido-trachealis and inferiorly to the
shoulder-joint. The superior portion touches the skin throughout
its entire length.

74 ANATOMY OF THE DOMESTIC FOWL

Action.—A tensor of the lateral cervical integument. It is an
auxiliary to the tensor patagii.

Platysma Myoides. Location.—The inferior portion of the throat.

Origin.—From the lower margin of the rami of the jaw. Just
inferior to the attachment of the masseter.

Fic. 18.—Muscles of the upper neck region, 1, Dermo-temporalis. 2, Cornu
of the os hyoideum. 3, Carotid artery. 4, Jugular vein. 5, Pneumogastric
merve. 6, Esophagus. 7, Trachea.

Insertion —From the point of origin it spreads out into a thin
fan-like layer and meets its fellow in the median raphe. It is
attached to the skin in this region.

Shape.—A very thin fan-shaped muscle.

Relations —Closely adherent to the skin.

Action.—Assists in supporting the lingual apparatus and superior
jarynx. Compresses and elevates the part.

MYOLOGY 75

Dermo-cleido Dorsalis. Location.—Anterior shoulder region.
Origin.—From the upper mesial part of the clavicular bone.
Insertion—Three fasciculi forming a fan-like arrangement at-
‘tached’ to the skin in the shoulder-joint and scapular region. The
extremities of the fasciculi may meet in the median line of the
dorsal region and merge with the dermo-dorsalis.

Shape.—Three fasciculi forming a fan-shaped radiation.

Relations —Superiorly with the skin. “Inferiorly with the shoulder-
joint.

Action.—Contracting with the origin as the fixed point, they
brace the skin over the forepart of the back. With the integumental
attachment as the fixed point, they aid in the act of respiration.

' Cleido-trachealis. Location—Extending from the shoulder to
the superior laryngeal region.

Origin.—From a small area on the antero-inner part of the middle
of the arm of the furcula.

Insertion—The fibers pass upward and become flattened and
attached to the skin and dermo-temporalis muscle. They touch
each other on the anterior border of the superior larynx, the trachea.
and the skin over these parts.

Shape.—A slender bundle of muscles.

Relations—Superiorly the skin, and internally the larynx and
the trachea. :

Action.—Controls the skin region of this part of the neck.

Dermo-spinalis. Location.—In the region of the shoulder.

Jrigin—In an attenuated: fascia from the crest of the neural
spines of the first, the second, and the third dorsal vertebre.

Insertion.—To the skin in a broad pale stratum, over the scapular
region.

Shape.—Thin, pale, and very delicate.

Relations —Superiorly with the skin, and inferiorly with the
shoulder.

Action.—Controls the skin of the region.

Dermo-iliacus. Location.—Along the back on either side of the
spine.

Origin.—From the inner angle of the marginal portion of the
antero-dorsal border of the ilium.

Insertion.—Passing forward as a delicate band it spreads out and
becomes lost in the skin of the shoulder region.

Shape.—Thin, delicate, and ribbon-shaped.

76 ANATOMY OF THE DOMESTIC FOWL

Relations —Superiorly with the skin.

Action.—If the posterior end is fixed, it will cause the feathers
to lie close to the skin. Its action would then be opposite to the
dermo-dorsalis. ,

Dermo-ulnaris. Location.—Outer surface of the anterior upper
costal and the posterior humeral region.

Origin.—By a thin fascia from the outer part of the third and the
fourth true ribs at the base of their epineural appendages. Also
from the fascia between them.

Insertion—The fibers pass forward and upward as a thick
.. muscular bundle and is loosely attached to the skin at a point just
back of the humerus. The tendon later becomes spread out and
attached to the fascia as far as the elbow-joint. It covers the
olecranon of the ulna. ;

Shape—At first rather thick, fascicular-like; later becomes
tendinous; and at its attachment it becomes spread out over the
olecranon.

Relation.—Inferiorly with the ribs and humerus, and externally
with the skin. ~

Action.—A depressor of the humeral region.

THE SKELETAL MUSCLES
THE MUSCLES OF THE HEAD

Temporal Masseter

Biventer maxille Entotympanicus

Pterygoideus internus Pterygoideus externus
Digastricus

Temporal (Fig. 19, No. 4). Location——Occupies the temporal
fossa.

Origin.—From the mesian line of the sphenotic process, and the
adjacent wall of the orbit.

Insertion ——The fibers passing downward and forward blend with
the fibers of the masseter. Inferiorly it inserts by a tendon to the
coranoid process upon the superior ramal margin of the mandible.
' Shape.—Fan-shaped with broad portion uppermost.

Relations.—It occupies the temporal fossa. It is related superiorly
with the dermo-temporalis and skin. Inferiorly, with the biventer
maxille and the masseter.

MYOLOGY 17

Action.—It aids in closing the jaw.

Masseter (Fig. 19, No. 1). Location.—Occupies the supero-lat-
eral portion of the surface of the lower jaw.

Origin.—In two portions: the first, by a broad and thin tendon
from the entire length of the bony ridge above the external auditory
meatus, from the squamosal process, and from the outer portion of
the quadrate bone; the second, from the side and under border of
the zygoma.

Insertion.—The first portion: The fibers pass downward and for-
ward beneath the zygoma; a few of the fibers blend with those of the
temporal; one tendon inserts to a small tubercle on the upper border
of the jaw behind the coronoid process, and by fleshy insertion
to the outer side of the ramus of the lower jaw, quite as far forward
as the horny portion of the beak. The second portion: by a small
tendon to the mandible on its upper border immediately in front of
the articular portion.

Shape.—Flat, and elongate. Somewhat fleshy.

Relations —Superiorly with the temporal, and inferiorly with the
biventer maxilla and stylo-hyoideus. Externally with the skin,
and internally with the jaw bone.

Action.—Aids in closing the jaw.

Biventer Maxille (Fig. 19, No. 3). Location——Covers the outer
posterior portion of the mandible.

Origin.—It arises in two portions: The first, from a ridge bounding
the posterior part of the auditory canal; the second, from a depres-
sion of the mesial side. These two parts blendand extend downward
and forward.

Insertion—To the posterior part of the articular end of the
mandible.

Shape.—A curved fleshy mass.

Relations.—Superiorly with the temporal and stylo-hyoideus.
Posteriorly with the digastricus and genio-hyoideus. Internally
with the jaw bone, and externally with the skin.

Action.—It aids in opening the jaw.

Entotympanic. Location.—Posterior to the pterygoid.

Origin.—From the side of the basi-sphenoid and from the base of
the rostrum immediately beyond it.

Insertion—The fibers pass downward and forward, and insert by a
double tendinous slip. One slip inserts to a spine-like process on

78 ANATOMY OF THE DOMESTIC FOWL

the upper side of the pterygoid, and the other to the quadrato-ptery-
goidean articulation.

Shape.—Spindle-shaped.

Relations.—Anteriorly with the pterygoid. Internally and pos-
teriorly with the basi-sphenoid. Externally with the pterygoideus
internus.

Action.—Aids in raising the upper mandible by pulling forward
the quadratus and pterygoidean against the palatines.

Pterygoideus Internus (Fig. 17, No. B, 5). (Synonym.—Ptery-
goideus medialis.)

Location.—A muscular mass at the roof of the mouth.

Origin.—From the major part of the surface of the palatine bone
and the distal head and shaft of the pterygoid and the sphenoidal
projection.

Insertion.—By a ack to the antero-internal part of the articular
part of the mandible.

Shape.—Fusiform with a thick fleshy belly.

Relations—Superiorly with the palatine, the pterygoid, and the
sphenoid bones. Inferiorly with the skin.

Action.—It aids in closing the jaw.

Pterygoideus Externus. (Synonym.—Pterygoideus lateralis.)

Location.—Supero-external to the pterygoideus internus.

Origin.—From the outer part of the extremity of the orbital proc-
ess of the quadrate.

Insertion —The fibers pass downward, outward and forward and
are inserted to the inner part of the mandibular ramus. :

Shape.—A small round bundle.

Relations —Inferiorly with the pterygoideusinternus. Externally
with the inferior maxilla.

Action.—Aids in closing the jaw.

Digastricus (Fig. 17, No. B, 16). Location —Extends from the
basi-temporal to the side of the neck.

Origin.—From the external lateral angle of the basi-temporal.

Insertion.—Opposite the angle of the jaw the fibers spread out in
fan-like arrangement. The muscle meets its fellow of the opposite
side; extends longitudinally over the superior larynx, for some
distance down the neck.

Shape—Thin and ribbon-shaped.

Relations —Externally to the platysma myoides. The anterior

1 According to international veterinary nomenclature.

MYOLOGY 79

fasciculi blend with those of the mylo-hyoideus; internally with the
larynx at the upper part. ;

Action.—To raise the trachea and hyoid apparatus against the
pharynx.

THE MUSCLES OF THE TONGUE

Mylo-hyoideus Stylo-hyoideus
Genio-hyoideus Cerato-hyoideus
Sterno-hyoideus Depressor-glossus
Cerato-glossus Hyoideus transversus

Mylo-hyoideus. Location—The forepart of the inter-ramal
space.

Origin.—From the inner side of the lower jaw at a point just
above the lower border and the inturned edge of the horny sheath of
the beak.

Insertion.—By aponeurosis to the under side of the hyoid, on the
median line between the first and the second basi-branchial.

Shape.—Thin, flat, and delicate.

Relations —Inferiorly with the skin. Thin and rather broad, it
meets its fellow of the opposite side. Laterally with the rami
of the jaw. Superiorly with the hyoid apparatus.

Action.—Lifts the tongue upward against the roof of the mouth.

Stylo-hyoideus (Fig. 17, No. B, 6). Location.—Supero-posterior
to the hyoid apparatus.

Origin.—From the outer portion of the articular enlargement of
the lower jaw.

Insertion.—By a tendon to the basi-branchial of the thyro-hyal.

Shape.—A long transversely flattened fasciculus.

Relations —Supero-posterior part of the hyoid apparatus along
side the genio-hyoideus and the cerato-hyoideus.

Action.—Singly, pulls the tongue to one side; acting with its
fellow, pulls the tongue upward.

Genio-hyoideus (Fig. 9, No. 7). Location.—Supero-posterior to
the hyoid apparatus.

Origin.—From the anterior portion of the inner side of the lower
jaw.

Insertion —To the middle of the outer side of the basi-branchial
of the corner of the os hyoides which cornu it completely envelops.

Shape.—A long, rather thick fasciculus.

Relations.—With the stylo-hyoideus and cerato-hyoideus.

80 ANATOMY OF THE DOMESTIC FOWL

Action.—Protrudes the tongue from the mouth.

Cerato-hyoideus (Fig. 9, No. 8). (Synonym.—Kerato hyoideus.)

Location.—Inferior to the hyoid apparatus.

Origin.—By a delicate tendinous slip from the under side of the
shaft of the basi-hyal element of the hyoid-apparatus.

Insertion.—To a small elevation on the under side of the anterior
end of the glosso-hyal.

Shape.—A small round muscular fasciculus becoming tendinous in
its anterior half.

Relations—Superiorly with the hyoid apparatus.

Action—Singly, pulls the tongue to one side; acting with its
fellow, depresses the tongue.

Sterno-hyoideus. Location.—Inferior to the hyoid apparatus.

Origin.—From the outer anterior surface of the thyroid bone of
the superior larynx.

Insertion —To the anterior part of the basi-hyal.

Shape.—At first broad and rather fleshy, becomes contracted and
somewhat tendinous.

Relations —Inferior to the hyoid apparatus and superior larynx.

Action.—When the larynx is fixed, acting alone deflects the tongue
laterally; acting with its fellow, depresses the tongue. If the base
of the tongue is fixed the two pull the larynx forward. Hence
muscles of deglutition.

Depressor-glossus. Location Superior to the basi-hyal.

Origin.—From the under portion of the basi-hyal.

Insertion.—To under part of the glosso-hyal.

Shape.—Small, short.

Relations.—Superiorly with the basi-hyal and glosso-hyal bones.

Action.—Depresses the tip of the tongue and elevates the base.

Cerato-glossus. Location.—On the upper portion of the cornu
of the hyoid.

Origin.—One-half of the surface of the first basi-branchial.

Insertion——To the upper side of the shaft of the cerato-branchial
element of the hyoid apparatus.

Shape.—A small muscular fasciculus.

Relations.—Supero-laterally to the cerato-branchial element.

Action.—Elevates the cornua of the hyoid arches and presses them
against the skull.

Hyoideus Transversus (Fig. 9, No. 9 and 10). Location—
Envelops the spur process of the euro-hyal.

MYOLOGY 8t

Origin and Insertion—It extends from the inner side of one cornu
to the spur process.

Shape.—Thin, flat.

Relations —Posterior to the euro-hyal, which it envelops, and
between the cornua of the os hyoides.

Action.—Approximates the cornua of the os hyoides.

THE CERVICAL MUSCLES

Complexus” Rectus capitis anticus minor
Flexor capitis inferior Rectus capitis posticus major’
Biventer cervicis Longus colli posti¢us- =.
Obliquus colli Longus colli anterior

Rectus capitis lateralis Trachelo-mastoideus
Interspinales,, - Interarticulares
Obliquo-transversales Intertransversales~

Scalenus medius”

Complexus (Fig. 19, No. 5). Location.—Supero-lateral portion
of the neck.

Origin.—By three tendinous slips from the antero-lateral portion
of the transverse process of the fourth, the fifth, and the sixth
cervical vertebra.

Insertion—The muscular fibers pass around the neck and meet
their fellows in the median line in a fascia formation. The thin
tendinous sheet inserts into the occiput just above the occipital
ridge.

Shape.—From point of origin this muscle expands into a broad
sheet.

Relations —It overlies the muscles of the occipital region.

Action.—It extends the head.

Rectus Capitis Anticus Minor (Fig. 19, No. 8). (Synonym.—
Rectus capitis ventralis minor.)

Location.—Infero-lateral portion of the neck.

Origin.—From the apices of the hyapophyses of the second,
the third, and the fourth cervical vertebe.

Insertion —To the occiput just below the complexus.

Shape.—A long and rather thick fasciculus.

Relations.—Externally with the skin. The tendinous slips of origin

pass between the flexor capitis inferior and longus colli anterior.
‘ 6

82 ANATOMY OF THE DOMESTIC FOWL

Action.—Extends the head.

Flexor Capitis Inferior (Fig. 19, No. 7). Location.—Antero-
inferior part of the neck.

Origin —From the apices of the hyapophyses of the second, the
third, and the fourth cervical vertebra.

Insertion—To the triangular area on the basi-temporal of ‘the
base of the cranium. :

Shape.—At first tendinous, becomes somewhat fleshy as it passes
forward. |

Fic. 19.—Muscles of the head and neck. 1, Masseter muscle. 2; Infra-
orbital sinus. 3, Biventer maxilla. 4, Temporalis. 5, Complexus. 6, Rectus
capitis posticus major. 7, Flexor capitis inferior. 8, Rectus capitis anticus
minor. 9, Biventercervicis. 10, Longuscolliposticus. 11,Obliquuscolli. 12,
Intertransversales. 13, Longus colli anterior.- 14, Lateral temporo-maxillary
ligament. 15, Lateral ligament of the jaw. 16, Trachelo-mastoideus. 17,
Rectus capitis lateralis. 18, Scalenus medius. 19, Rhomboideus. 20, Tra-
pezius. 21, Locationofscapula. 22,Supraspinatus. 23, Teres et Infraspinatus.

Relations.—Antero-inferior portion of the neck close to the rectus
capitis anticus minor.

Action.—Flexes the head upon the neck.

Rectus Capitis Posticus Major (Fig. 19, No. 6). (Synonym.—
Rectus capitis dorsalis major.)

Location.—Supero-lateral area on the anterior portion of the
neck.

Origin.—From the median anterior aspect of the second cervical
vertebra, and the supero-anterior border of the neural canal.

MYOLOGY 83

Insertion.—To the crescent-shaped area at the back of the skull.

Shape.—Short, thick, fleshy bundle.

Relations —Superiorly with the complexus; inferiorly with the
trachelo-mastoideus and the vertebre.

Action.—Singly, pulls the head to one side; acting with its fellow,
extends the head.

Biventer Cervicis (Fig. 19, No. 9). Location —Occupies the su-
perior part of the neck.

Origin—From the side of the neural spine of the first dorsal
vertebra, and from the adjacent tendon of the longus colli posticus.

Insertion.—To the occiput.

Shape-—Tendinous in the middle with a more or less spindle-
shaped belly at each end.

Relations.—Superior to the longus colli posticus. It lies next to
the skin.

Action.—Extends the head on the neck and elevates the neck.

Longus Colli Posticus (Fig. 19, No. 10). (Synonym.—Longus
colli dorsalis.)

Location.—Occupies the superior part of the neck.

Origin.—From the marginal edges of the summits of the neural
spines of the first two dorsal vertebre.

Insertion—To the transverse process of the axis, and superior
part of the cervical vertebre.

Shape.—A long, somewhat narrow, flattened muscle, the inferior
portion of which is divided into five or six fasciculi.

Relations.—Superiorly with the biventer cervicis and inferiorly
with the vertebrz.

Actton.—Raises the neck upward.

Obliquus Colli (Fig. 19, No. 11). Location.—On the lateral side
of the neck.

Origin and Insertion.—The first of the seven fasciculi originates
from the diapophysis of the eleventh cervical vertebra, winds ob-
liquely over the tenth, and is inserted into the posterior margin
of the postzygapophysis of the ninth vertebra. In its passage it
receives the slip from the longus colli posticus. The next fasciculus
originates from the transverse process of the tenth cervical vertebra,
winds obliquely over the ninth vertebra, and is inserted to the post-
zygapophysis of the eighth vertebra. ~ In its passage it also receives
a fasciculus from the longus colli posticus. The next three fas-
ciculi originate in a similar manner being attached to similar post-

84 ANATOMY OF THE DOMESTIC FOWL

zygapophyses and have slips extending forward which slips are in-
serted to the neural spines of the alternate vertebre.* The sixth
fasciculus originates from the transverse process of the sixth ver-
tebra, passing obliquely up the neck is inserted to the extremity of
the diapophysis of the fourth vertebra, the outer extremity of the
transverse process of the third vertebra. The seventh, or anterior,
fasciculus originates from the transverse process of the fifth vertebra,
and is inserted to the extremity of the diapophysis of the third
vertebra.

Shape.—Short, thick fasciculi.

Relations.—Laterally with the vertebre. Inferiorly with the
intertransversales. Superiorly with the longus colli posticus, and
externally with the skin.

Action.—Flexes one vertebra on the other laterally.

Longus Colli Anterior (Fig. 19, No. 13). (Synonym.—Longus
colli ventralis.)

Location.—Occupies the anterior portion of the neck.

Origin and Insertion——This muscle is divided into a vertical
portion, and a superior and an inferior oblique portion. The ver-
tical portion originates from the hypophyses of the tenth to the fif-
teenth vertebra and is inserted by a tendon to the tubercle on the
inferior portion of the atlas. Small, slender tendons are given off
and insert to the apices of the parapophyses of the fourth to the
tenth cervical vertebre.- There is more or less attachment to
the bodies of the cervical vertebra mentioned. The superior
oblique portion originates from the diapophyses of the third, the
fourth, the fifth cervical vertebra and becoming tendinous is in-
serted to the tubercle on the inferior portion of the body of the atlas.
The inferior oblique portion originates from the transverse processes
of the fourth, the fifth, and the sixth cervical vertebre. It is
inserted by a slender tendon to the apex of the parapophysis of
the third cervical vertebra.

Shape.—A long fleshy muscle extending the entire length of the neck.

Relations.—Inferiorly with the skin and superiorly with the cer-
vical vertebre.

Action.—Pulls the néck downward.

Rectus Capitis Lateralis (Fig. 19, No. 17). Location.—The
infero-lateral anterior portion of the neck.

Origin.—Originates tendinous from the diapophysis of the third,
the fourth, and the fifth cervical vertebre.

MYOLOGY 85

Insertion.—Passes obliquely upward in front of the spinal column
to the inner tubercle on the basal ridge of the basi-temporal bone,
by a subcompressed tendon.

Shape.—A somewhat thick fasciculus.

Relations—Superiorly with the trachelo-mastoideus, inferiorly
with the longus colli anterior, and externally with the skin.

Action.—Singly, pulls the head down and to one side; acting with
its fellow, pulls the head downwad.

Trachelo-mastoideus (Fig. 19, No. 16). (Synonym.—Longissi-
mus capitis et atlantis.)

Location.—Laterally on the anterior portion of the neck.

Origin —Semitendinous from the diapophyses of the second, the
third, the fourth, and the fifth cervical vertebre.

Insertion—By subcompressed tendon to the base of the cranium,
at the outer tubercle of the basal ridge of the basi-temporal.

Shape.—Flattened from side to side; broad at the posterior por-
tion, becomes angular at the anterior portion.

Action.—Singly, pulls the head down and to one side; acting with
its fellow, pulls the head downward.

Interspinales (Fig. 17, A, No. 2). Location.—Superior to the.
vertebra.

Origin and Insertion.—A series of muscles connecting the superior
neural spines of the cervical vertebre.

Shape.—Thin, flat.

Relations.—Anteriorly the posterior border of the vertebre in front
and posteriorly the anterior border of the succeeding vertebre,
inferiorly by the vertebre.

Action.—To approximate the spinous portion of the vertebra.

~~ Interarticulares (Fig. 17, No. A, 4). Location.—Supero-laterally
to the vertebre. Between the postzygapophysis.

Origin and Insertion.—From the posterior margin of the ring of
the: atlas to the postzygapophysis of the axis. Then in the suc-
ceeding vertebre from the postzygapophysis of the vertebra to
the same of the succeeding vertebra.

’ Shape.—Muscular bundle. _

Relations.—Inferiorly with the vertebre. Supero-laterally with
the obliquo-transversales.

Action.—Aids in approximating the vertebre in a supero-lateral
direction.

86 ANATOMY OF THE DOMESTIC FOWL

Obliquo-transversales (Fig. 17, A, No.1). Location.—Supero-
lateral to the vertebre.

Origin and Insertion——Passes obliquely from the transverse
process of one vertebra to the postzygapophysis of the vertebra
beyond.

Shape.—A thin fasciculus.

Relations.—Inferiorly with the interarticulares and laterally with
the intertransversales. :

Action.—Aids in flexing the vertebre supero-laterally.

Intertransversales (Fig. 19, No. 12). Location—Laterally to the
vertebre.

' Origin and Insertion——Extend between the transverse processes
beginning at the third cervical vertebra.

Shape.—Short, thick.

Relations —Laterally the vertebre. Superiorly the obliquo-
transversales.

Action.—Aids in flexing the-vertebre laterally.

Scalenus Medius (Fig. 19, No. 18). (Synonym.—Scalenus.)

Location.—Supero-laterally to the entrance of the thorax.

Origin.—From the diapophysis and pleurapophysis of the eleventh
cervical vertebra.

Insertion —To the entire border of the first rib. A few fibers
pass over to the anterior free margin of the middle third of the
second rib.

Shape.—Rather pyramidal in shape with base uppermost.

Relations —Posteriorly with the levatores costarum. Internally
with-the longus colli.

Action.—When the first rib is fixed singly, turns the neck to one
side; acting with its fellow, extends the neck. When the neck is
fixed, by drawing the first rib forward, it acts as an inspiratory
muscle.

THE MUSCLES OF THE AIR PASSAGES

The Superior Larynx

Constrictor glottidis Thyreo-arytenoideus
The Inferior Larynx
Tracheo-lateralis Broncho-trachealis posticus
Broncho-trachealis anticus Broncho-trachealis brevis
Bronchialis posticus Bronchialis anticus

Sterno-trachealis

MYOLOGY 87

Constrictor Glottidis. Location.—Supero-anterior portion of the
superior larynx.

Origin.—From the superior and longitudinal line of the thyroid
plate.

Insertion—All along the inner margin of the arytenoid bone, and
to the apex of the mid-cricoidal segment.

Shape.—Thin, flat sheet extending outward and upward, and then
inward.

Relation.—Inferiorly with the larynx.

Action.—The two muscles of this kind acting together, close the
glottis by drawing the apices of the arytenoids to the median line.

Thyreo-arytenoideus. Location.—Supero-lateral portion of the
superior larynx.

Origin.—From the entire outer margm of the thyroid plate and
the outer margin of the cricoid bone.

Insertion —All along the outer margin of the arytenoid bone and
the outer border of the central cricoid piece.

Shape.—A thin, flat sheet.

Relations.—Infero-laterally with the superior larynx.

Action.—The two muscles of this kind acting together, open
the glottis by pulling the arytenoid bone outward.

Tracheo-lateralis (Fig. 20, No. 2). Location—Along the lateral
side of the trachea.

Origin.—By the union of the bronchio-trachealis posticus and
bronchio-trachealis anticus, on the lateral side of the trachea,
about 114 centimeters from the bifurcation of the trachea.

Insertion—In delicate fan-like structure to the side of the
trachea, near the superior larynx.

Shape.—Thin, ribbon-shaped, closely attached to the trachea.

Relations —Internally with the trachea, and externally with the
skin and other integument.

Action.—Acts as a brace to the sides of the trachea, and contract-
ing, approximates the tracheal rings and thus shortens the trachea.

Broncho-trachealis Posticus (Fig. 21, No.3). Location.—Postero-
superior portion of the trachea. The fibers pass downward and
backward. |

Origin.—From the inferior end of the tracheo-lateralis.

Insertion.—To the end of the third half of the bronchial ring of
the same side.

Shape.—A small fasciculus.

88 ANATOMY OF THE DOMESTIC FOWL

Relations.—Internally with the trachea, and externally with the
skin and other integument.

Fic. 20.—The anterior pectoral region. 1, Sterno-trachealis. 2, Tracheo-
lateralis. 3, Broncho-trachealis brevis. 4, Costal process of sternum. 5, Right
and left carotid converging and occupying same sheath at6. 7, The heart
showing branches of coronary artery. 8, Cervical air-sac. 9, Left’|brachio-
cephalic artery. 10, Right brachio-cephalic artery. 11, Trachea. 12, Inferior
larynx. 13, Subclavian artery. 14, Carotid trunk. 15, Internal thoracic
artery. 16 Thyroid gland. 17, Anterior venacava. 18, Auricular appendage.

Fic. 21.—The inferior tracheal region. 1, Bronchialis anticus. 2, Bronchialis
posticus. 3, Broncho-trachealis posticus. 4, Broncho-trachealis anticus.

Action.—A tensor of the true or inferior larynx.
Broncho-trachealis Anticus (Fig. 21, No. 4). Location.—Anterior
portion of the inferior extremity of the trachea.

MYOLOGY 89

Origin.—The anterior branch ofthe bifurcated tracheo-lateralis.

Insertion —To the anterior extremity of the third half ring of the
bronchus of the same side.

. Shape.—A small fasciculus.
_ Relations —Internally with the trachea, and externally. with the
skin and other integument.

Action.—A tensor of the inferior larynx.

Broncho-trachealis Brevis (Fig. 20, No. 3). Location. —Posterior
part of the inferior extremity of the trachea.

Origin.—From just beneath the broncho-trachealis anticus muscle.

Insertion —Extends obliquely across the inferior larynx and is
inserted to the posterior end of the second bronchial ring.

Shape.—Rather short, strong, straight, subcylindrical.

Relations.—Internally with the trachea, and laterally with the
broncho-trachealis posticus.

Action.—A tensor of the inferior larynx.

Bronchialis Posticus (Fig. 21, No. 2). Location.—Supero-lateral
side of the anterior end of the bronchi.

Origin.—From the lateral inferior margin of the last tracheal ring.

Insertion —Passing obliquely across the larynx it inserts to the
posterior extremity of the second half ring of the bronchus.

Shape.—Small, thick, spindle-shaped.

Relations.—Internally with the trachea, inferiorly with the bron-
chialis anticus, and superiorly with the broncho-trachealis brevis.

Action.—A tensor of the larynx. :

Bronchialis Anticus (Fig. 21, No. 1). Location.—Inferior to the
former muscle.

Origin ——From the last ring of the trachea.

” Insertion ——The fibers pass obliquely forward and become in-
serted to the rim of the arytenoid cartilage of the inferior larynx,
and the anterior extremities of the first and second half rings of
the bronchus.

Shape.—Thick, spindle-shaped; about twice the size of the bron-
chialis posticus.

Relations—It is crossed at its origin by the broncho-trachealis
anticus and is related internally with the bronchus and end of the
trachea.

Action.—A tensor of the larynx.

Sterno-trachealis (Fig. 20, No. 1). Location —The inferior re-
gion of the trachea above the above-named muscles

go ANATOMY OF. THE DOMESTIC FOWL

Origin.—From the side of the trachea beneath the posterior border
of the broncho-trachealis anticus. _

Insertion —Passes downward and backward across the cavity of
the chest and is inserted to the inner part of the costal process of the
sternum.

Shape.—A delicate cord of fibers.

Relations —Internally with the broncho-trachealis muscles.

Action.—A relaxor of the larynx, and hence, of the tympanic
membrane.

THE STERNAL GROUP

Triangularis Sterni. Location—In the floor of the thoracic
cavity.

Origin —From the entire superior margin of the summits of the
costal processes.

‘Insertion.—The fibers extend upward and ‘backward, dividing into
four digitations which cover the inner surface of the three principal
sternal ribs, and are inserted to the first four as high as their
articulations with the vertebral ribs.

Shape.—Flat and somewhat triangular.

Relations.—Inferiorly with the floor of the thoracic cavity.

Action.—A powerful muscle of expiration. In contracting, les-
sens the cubic content of the thorax.

The Diaphragm (Fig. 47, No. 10; Fig. 33, No. 9). Description.—
The diaphragm in the domestic fowl is rudimentary. It consists of
a thin semi-transparent membrane, situated between and separating
the thoracic and the abdominal cavities. It readily conforms to the
various organs pressing upon it from each side. On each side are
three rudimentary muscles which extend from the vertebral heads of
the second, the third, and the fourth sternal ribs. The fibers of
these muscles spread out in fan-like upon the diaphragm, and are
seen just above the digitations of the triangularis sterni.

THE ABDOMINAL MUSCLES
Obliquus abdominis externus Obliquus abdominis internus

Rectus abdominis Transversalis abdominis

Obliquus Abdominis Externus (Fig. 22, No. 1). Location The
outermost muscle of the lateral abdominal wall.

MYOLOGY. ot

"Attachments —By a delicate aponeurotic membrane, from the sides

" of all the true dorsal ribs, from the posterior border of the last ver-
tebral rib and the adjoining margins of the pelvis, and from the
entire posterior surface of the inferior border of the post-pubic
element of the pelvis; by aponeurosis, blending with the fascia to-
ward the root of the tail and lower part of the abdomen; and by
aponeurosis to the sides of the sternum, to the under part of the
pectoralis major muscle, and to the zyphoid prolongation. Also
by aponeurosis it meets its fellow from the opposite side, at the
linea alba.

Fic. 22.—The abdominal muscles of a hen. Right side. 1, Obliquus ab-
dominis externus. 2, Obliquus abdominis internus. 3, Peritoneum covering
intestines. 4, Peritoneum covering the gizzard. 5, The lungs (note how small
they are from a relative standpoint). 6, The great sciatic or ischiadic nerve.
7, Lumbar nerves. 8, Kidney. 9, Brachial plexus. 10, Pericardium of the
base of the heart. 11, Anterior vena cava. 12, Oil gland. 13, Showing a
sacculation of the abdominal muscles. There is no tunica abdominalis in the
fowl.

Obliquus Abdominis Internus (Fig. 22, No. 2). Location.—Just
internal with regard to the external oblique.

Attachments ——By aponeurosis, from the posterior third of the
post-pubic element of the pelvis; by muscular fibers, from the bal-
ance of the bone; and by a few fibers, from the iliac border posterior
to the acetabulum. Anteriorly, these fibers are inserted to the
entire posterior margin of the last vertebral rib, and into the pleura-
pophysial head of the last costal rib. «

Rectus Abdominis (Fig. 13, No. 10 and Fig. 23, No.1). Location.—
The inferior median abdominal wall.

Q2 ANATOMY OF THE DOMESTIC FOWL

Attachments.—By aponeurosis, from the distal extremity of the
post-pubic element of the pelvis and from the semitendinous liga-
ment which stretches from one post-pubic tip to the other. Attaches
anteriorly to the zyphoid margin of the sternum, and passes, by a
broad aponeurotic membrane, over the outer surface of the thoracic
wall beneath the external oblique.

Transversalis Abdominis (Fig. 25, No. H, 1). Location.—Infero-
lateral portion of the abdominal wall.

Attachments.—By a. thin, tendinous attachment from the entire
post-pubic and iliac margins of the pelvis and from the interpubic
ligament. Its fibers cross the abdomen between the peritoneum,
the rectum, and the internal oblique. It is inserted over the entire
pleural part of the last two vertebra] ribs, the intercostal muscles
between them, and the same surface of the hemapophyses connected |
below. Inserts into the linea alba.

Action.—The abdominal muscles give support to the abdominal
organs, aid in flexing the spine, draw the last rib backward, thus
aiding in respiration, and compress the abdominal organs to aid
in defecation and expiration.

THE DORSO-LUMBAR REGION

Sacro-lumbalis Longissimus dorsi

Sacro-lumbalis. Location.—The latera] lumbo-sacral region.

Origin.—Tendinous from the anterior margin of the ilium, from the
angles of the last two vertebral ribs, and by tendinous slips, from
the outer ends of the transverse processes of the last three dorsal
vertebra.

Insertion.—By a few fleshy fibers into the angle of the first dorsal
rib and to the corresponding points upon the free cervical ribs,
and by a strong semitendinous insertion into the outer extremity of
the diapophysis of the twelfth cervical vertebra.

Shape.—A close fitting, tendo-muscular sheet extending between
the anterior margin of the ilium and the root of the neck.

Relations.—Intimately blended with the longissimus dorsi ex
ternally.

Action.—Assists the longissimus dorsi.

Longissimus Dorsi (Fig. 24, No. 4). Location—The superior
dorso-lumbar region.

MYOLOGY 93

Origin.—From the inner portion of the anterior margin of the
ilium, and from the various surfaces afforded by its walls and the
walls of the ilio-neural canal; by a series of short. and distinct ten-
dons alternately from the anterior and posterior extremities of the
summits of the neural spines of all the dorsal vertebra. From the
diapophyses of the dorsal vertebrae, from the crests of the neural
spines of the last three dorsal vertebrz, from the bodies of the dorsal
vertebre, and from the fascia between them and the sacro-lumbalis;
and also by a tendinous sheet continuous with the origin of the lon-
gus colli posticus.

Insertion.—By four fasciculi into the free posterior margins of
the oblique processes of the eleventh, the twelfth, the thirteenth,
and the fourteenth cervical vertebra.

Shape.—A large flat sheet.

Relations—Laterally, with the superior spinous processes of the
vertebre, and with the superior surface of the ribs.

Action.—Singly, flexes the back laterally; with its fellow, aids in
elevating the body upward.

THE COCCYGEAL MUSCLES

Levator coccygis Levator caude
Transversus peronei Depressor caudz
Depressor coccygis Lateralis caude
Lateralis coccygis Infracoccygis

Levator Coccygis (Fig. 23, No. 2). Location.—The superior part
of the caudal apparatus.

Origin.—From a limited area of the ilium just beyond and to the
side of the anterior free caudal vertebre.

Insertion.—Into the tuberosity of the anterior margin of the
pygostyle.

Shape.—Short, fleshy.

Relations.—Superior portion of the coccygeal vertebre.

Action.—Elevates the tail.

Levator Caude (Fig. 23, No. 4). Location.—Supero-lateral side
of the tail.

Origin.—From the posterior surface of the post-acetabular area of
the pelvis, and from the superior surface of all the coccygeal ver-
tebrz except the pygostyle.

94 ANATOMY OF THE DOMESTIC FOWL

Insertion.—To the four inner quill butts of the main tail feathers.

Shape.—Long, spindle-shaped.

Relations.—Internally, with the levator coccygis and externally,
with the lateralis caude. .

Action.—Powerfully elevates the four inner main tail feathers.

_Transversus Peronei (Fig. 23, No. 3). Location.—The posterior
abdominal region. ,

Fic. 23.—Outer layer of muscles of the tail and thigh. 1, Rectus abdominis.
2, Levator coccygis. 3, Transversalis peronie. 4, Levator caudz. 5, Lateralis
caude. 6, Depressor caude. 7, Sartorius. 8 and 9, Gluteus primus. 10,
Semitendinosus. 11, Gastrocnemius. 12, Peroneus longus. 13, Flexor per-
foratus indicis secundus pedis. 14, Flexor perforatus medius secundus pedis.
15, Lateral ligament of the hock.

Origin.—From the entire posterior margin of the ischium, and
from the posterior margin of the post-pubis extending beyond it.
Insertion.—Becoming aponeurotic, it passes toward the coccyx
and is attached to the entire posterior margin of the ilium. Passes
to the median line, meeting its fellow in front of the anus. _
Shape.—Thin, sheet-like.

MYOLOGY 95

Relations.—Infero-anteriorly with the anus. Posteriorly with the
edges of the ilium and of the ischium. Internally with the depressor
caude. ,

Action.—Gives support to the viscera in the post-anal region,
and aids in attaching the anus to the structures above.

Depressor Caudz (Fig. 23, No. 6). Location.—The infero-lateral
side of the tail.

Origin-—From the lower half of the posterior border of the is-
chium, and from the entire posterior border of the post-pubis beyond.

Insertion.—To the quill butts of the three or four outer main
tail feathers.

Shape.—Strong, conical.

Relations.—Externally, with the depressor coccygis.

Action.—Singly, pulls the tail downward and outward; with its
fellow, pulls the tail downward.

Depressor Coccygis. Location—The outermost of the infero--
lateral muscles of the tail. F

Origin.—From the lower half of the posterior margin of the ischium
and the anterior three-fourths of the posterior margin of the post-.
pubic element of the pelvis beyond it.

Insertion—To the thickened rim of the inferior and expanded
portion of the pygostyle.

Shape.—Flat, triangular.

Relations. —Internally with the depressor caude.

Action.—Singly, pulls the tail downward and to one side; with its
fellow, pulls the tail downward.

Lateralis Caude (Fig. 23, No. 5). Location.—The lateral side of
the tail.

Origin.—From the tip of the transverse process of the first free
caudal vertebre.

Insertion.—To the outer three quill butts of the main tail feathers.

Shape.—Four fasciculi forming a fleshy belly.

Relations.—Inferiorly, with the levator caude and superiorly with
the depressor caudz.

Action.—Singly, pulls the tail downward and outward; with its
fellow, pulls the tail downward. The outermost fasciculus con-
tracting, spreads the tail feathers. ~

Lateralis Coccygis (Fig. 25, No. EZ, 2). Location.—The infero-
lateral side of the caudal vertebre.

- Origin.—From the surface of the posterior end of the ilium and by

96 ANATOMY OF THE DOMESTIC FOWL

tendons from the under side of the ends of the first three or four
caudal vertebre.

Insertion —To the side of the posterior margin of the expanded
portion of the pygostyle.

Shape.—Subcompressed mass.

Relations —With the transverse processes of the caudal vertebra,
inferiorly. :

Action.—Controls the lateral movements of the tail and its
feathers, and the oblique downward movement.

Infracoccygis (Fig. 25, No. E, 1). Location—The extreme in-
ferior portion of the caudal vertebre.

Origin.—From the inferior surface of the diapophysis of the last
vertebra which anchyloses with the pelvic sacrum, and from all the
free caudal vertebrz.

Insertion.—Into the lower side of the pygostyle.

Shape.—F lat, somewhat triangular.

Relations.—Superiorly, with the vertebra, laterally, with the
lateralis coccygis, and mesially, with its fellow of the opposite side.

Action.—Depresses the tail.

THE COSTAL REGION.

Latissimus dorsi Trapezius
Rhomboideus Serratus magnus anticus
Serratus parvus anticus Teres et infraspinatus
Intercostales Levatores costarum

Appendico-costales

Latissimus Dorsi (Fig. 24, No. 7). Location—Supero-lateral por-
tion of the dorsal region.

Origin.—From two portions, the anterior slip from the outer edge
of the superior margins of the neural spines of the second and the
third dorsal vertebre, and the second portion from a similar point
on all the succeeding dorsal vertebrae. The second portion is fascia-
like in its attachments.

Insertion.—The fibers converge toward the humerus and enter
between the deltoid the scapular head of the triceps and the re-
maining heads of this muscle and is inserted to the anconal part
of the humerus, just within in the radial crest.

MYOLOGY 97

Shape.—Thin, triangular.

Relations —Superiorly, with the skin. The most superficial of the
dorsal muscles. ;

Action —To elevate the humerus and thus flex the shoulder-joint.
An expiratory muscle when the wing is fixed.

Trapezius (Fig. 19, No. 20). Location.—In the shoulder region,
just below the longissimus dorsi.

Origin.—From the neural spines of the second, the third, the fourth,
and the fifth cervical vertebre just below the latissimus dorsi.

Insertion.—To the mesian upper border of the scapula.

Shape.—A flat oblong layer of fibers.

_ Relations—The posterior part of the trapezius overlies the an-
terior part of the rhomboideus. The posterior two-thirds is covered
by the latissimus dorsi. The anterior third is superficial.

Action.—Draws the scapula forward.

Rhomboideus (Fig. 19, No. 19). Location.—Supero-posterior
scapular region.

Origin.—From the neural spines of the first four dorsal vertebre
beneath the latissimus dorsi and trapezius muscles.

Insertion.—The fibers passing outward and backward attach to the
posterior third of the mesial or upper border of the scapula.

Shape.—Thin, flat, delicate.

Relations—Superiorly, by the latissimus dorsi and the trapezius.

Action—To draw the free end of the scapula- upward and
forward.

Serratus Magnus Anticus (Fig. 13, No. 16). Location.—The
supero-lateral side of the thorax. _

Origin.—By three strong digitations: first, from the outer part of
the second true rib just above the base of the epineural appendage;
the other two, from similar locations on the two succeeding ribs,
just above the origin of the dermo-ulnaris.

Insertions —The first by tendinous attachment to the interpleura-
pophysial membrane. The rest of the fibers pass upward and
slightly forward, and are inserted to the inferior surface of the
apex of the scapula.

Shape.—Three flat, strong digitations.

Relations.—Internally, with the ribs.

Action.—If the scapula is fixed, it is a muscle of inspiration.

Serratus Parvus Anticus. Location —The outer and upper sur-

face of the anterior part of the thorax.
7

98 ANATOMY OF THE DOMESTIC FOWL

Origin.-—By three digitations from the outer surface of the first
three ribs above the origin of the serratus magnus anticus and the
thoraco-scapularis.

Insertion —The thin sheet of fibers passes upward and backward,
and is inserted to the inferior margin of the scapula.

Shape.—Thin, flat.

Relations —Internally, with the ribs.

Action.—If the scapula is fixed, it is a muscle of respiration.

Teres et Infraspinatus (Fig. 13, No. 11). Location—Scapular
region. ‘
Origin.—From the superior surface and outer margin of the pos-
terior two-thirds of the scapula.

Insertion —The fibers pass forward and outward, and insert to the
humerus at the middle of the ulnar margin of the pneumatic fossa,
between the forks of the triceps. ,

Shape. —Flat, triangular-shaped. .

Relations —Anteriorly, with the supraspinatus. Internally, with
the ribs.

Action.—Aids in keeping the humerus in its socket. Assists in
closing the wing by drawing the humerus to the side of the body.

Intercostales (Fig. 24, No. 5). Location Between the ribs of the
upper thoracic region.

Origin and Insertion——From the anterior border of one rib, the
fibers, passing obliquely upward and forward, and the lower portion
downward and forward, are inserted to the posterior border of the
rib just in front.

Shape.—They are best developed in the anterior portion of the
thoracic region and extend down as far as the sternal ribs.

Relations —Internally the pleura, and anteriorly and posteriorly
the ribs.

Action.—The first rib being rendered fixed by the scalenus me-
dius, the muscles draw the ribs forward, thus aiding inspiration.

Levatores Costarum (Fig. 24, No. 2). Location—Supero-lateral
portion of the thorax.

Origin and Insertion.—A series of muscles, the first of which
extends from the extremity of the transverse process of the twelfth
vertebra, the fibers passing downward and backward to the anterior
free margin of the upper third of the long posterior rib, and to
the external surface close to its margin. The others arise and
insert in a similar manner from the ends of the diapophyses of all

MYOLOGY 99

the dorsal vertebre and attach to each succeeding rib. Those in
front are best developed.

Shape.—Thin and triangular.

Relations.—External to the intercostales.

Action.—Aids in respiration.

Appendico-costales (Fig. 24, No.1). Location.—The lateral side
of the thorax.

Origin and Insertion—From the posterior edge of an uncinate
process or epineural appendage, the fibers extending downward
and backward to the outer. surface of the succeeding rib.

Shape.—A series of thin triangular-shaped muscles.

Relations.—Internally, with the intercestales.

Action.—Aids in respiration.

THE ANTERIOR PECT@RAL GR®UP

Tensor patagii longus Tensor patagii brevis

Tensor Patagii Longus (Fig. 15C, No. 1; Fig. 14, No. 2). Loca-
tion.—Anterior shoulder region, in the triangular patagium of the
wing.

Origin.—By a flat tendon common to it and the tensor patagii
brevis from the supero-mesial line of the head of the clavicle. ©

Insertion.—By a long slender tendon extending in the duplicature
of the patagium, with which the fibers blend. Passing to the side
of the extensor metacarpi radialis longus, it extends over the end
of the radius and is inserted to the os carpi radiale, and to the fascia
which binds down the other tendons on the anterior part of the wrist-
joint.

Shape.—Cone-shaped belly terminating in a long tendon.

Relations.—Externally, with the skin; by its tendon, with the
border of the extensor metacarpi radialis longior.

Action.—Tenses the soft part in the fold of the wing, and aids in
flexing the forearm. ; :

Tensor Patagii Brevis (Fig. 14, No. 3). Location.—In the trian-
gular patagium of the wing.

Origin-—From the head of the clavicle in common with the
preceding.

Insertion.—The tendon bifurcates, one branch blending with the
fascia of the extensor metacarpi radialis longior, the other inserting
just below the tubercle on the extérnal condyle of the humerus.

100 ANATOMY OF THE DOMESTIC FOWL

Shape.—Fleshy; somewhat broader and longer than the preceding.
Relations.—Inferiorly, with the preceding.
Action.—Assists the tensor patagii longus in flexing the forearm.

THE PECTORAL MUSCLES

Pectoralis major Pectoralis secundus
Pectoralis tertius

Pectoralis Major (Fig. 13, No. 5). Location—On the lateral
side of the sternum.

Origin.—From the posterior portion of the lateral wing of the
sternal body, from the outer marginal third of the keel of the
sternum, and from the entire outer side of the limb of the furcula or
clavicle.

Insertion—The fibers converging form toward the proximal
third of the humerus a broad tendon which by its insertion covers the
entire palmar part of the pectoral crest. A few of the tendinous
fibers pass. over the shoulder-joint and blend with the long head of
the biceps. Near this point it receives the insertion of the dermo-
humeralis.

Relations. —Inferiorly, with the skin; superiorly, in the sternal
region, with the pectoralis secundus and the pectoralis tertius.

Shape.—Fleshy; largest of the pectorales.

Action.—Powerfully depresses the humerus. The chief muscle
of flight.

Pectoralis Secundus (Fig. 13, No. 9; Fig. 15, No. A, 6). Lo-
cation.—The entire lateral side of the sternum.

Origin.—From the anterior sternal extremity of the lower third
of the coracoid, from the keel and sternal wing, and by a tendon
from a membraneous expansion between the coracoid and the
clavicular bones and from the lower third of the coracoid.

Insertion —The fibers converge into a tendon, which passes up-
ward around the coracoid to its posterior through a canal formed by
the scapula, the coracoid, and the clavicle, the foramen triosseum
(Fig.15,No.A,7). This tendon then passes outward and downward,
and becoming flat, inserts to the humerus just anterior to the radial
crest and nearer to the humeral head than does the pectoralis major.

Relations.—Internally, with the breast-bone; externally, with the
pectoralis major; and superiorly, with the pectoralis tertius.

MYOLOGY IoI

Shape.—Long, fusiform, fleshy.

Action.—Raises the wing.

Pectoralis Tertius (Fig. 13, No. 6; Fig. 15, No. A, 5). Location.—
On the antero-lateral side of the sternum.

Origin—From the anterior half of the exterior of the body of
the sternum, from the fascia of the subclavius on the outer border
of the costal process, and from the outer, lower third of the
coracoid process.

Insertion.—The fibers pass upward to the outer side of the coracoid,
and becoming tendinous as they reach the humerus, by a strong
flattened tendon insert to the ulnar crest of the humerus on the
proximal margin at about a middle point of the pneumatic fossa.

Relations—Externally, with the pectoralis major; inferiorly,
with the pectoralis secundus; internally, with the fascia of the sub-
clavius and the sternum.

Shape.—Fleshy, fusiform.

Action.—Assists the pectoralis secundus in elevating the humerus.

MUSCLES OF THE SCAPULAR REGION

Coraco-humeralis Scapulo-humeralis
Supraspinatus Subclavius
Coraco-brachialis Teres minor
Levator scapule Thoraco-scapularis
Subscapularis

Coraco-humeralis. Location.—The scapulo-humeral region.

Origin.—From the outer side of the head of the coracoid, supero-
laterally to the long head of the biceps.

Insertion —To the palmar part of the head of the humerus just
inside of the insertion of the pectoralis major.

Shape——A delicate subcylindrical muscle.

Relations.—Superior to the head of the humerus.

Action.—Aids in extending the humerus.

Scapulo-humeralis (Fig. 14, No. 10). Location.—The scapulo-
humeral region.

Origin.—From the inner side of the neck of the scapula just within
the head of the deltoid.

Insertion.—Passing over the top of the shoulder-joint it is inserted
to the palmar part of the humeral head between the insertion of
the pectoralis major and the pectoralis secundus.

102 ANATOMY OF THE DOMESTIC FOWL

‘Shape.—Narrow, flat ribbon.

Relations—Along the upper margin of the larger portion of the
deltoid.

Action.—Aids in extending the humerus.

Supraspinatus (Fig. 19, No. 22). Location—Scapular region.

Origin.—From the superior surface and outer third of the scapula.

Insertion—To the lower border of the pneumatic fossa of the
humerus.

Shape.—Thin, flat, triangular.

Relations —Externally, with the trapezius and posteriorly, with
the teres et infraspinatus.

Action.—If the scapula is the fixed point it will pull the humerus
upward and backward.

Subclavius. Location.—Anterior sternal region.

Origin.—From the entire outer surface of the sternal process of
the sternum and the adjacent outer surfaces of three or four of
the hemapophyses.

Insertion.—To the inferior margin of the coracoid bone, the longer
fibers passing over to the fossa in the lower third of the posterior
part of the coracoid.

Shape.—Rather small, fleshy.

Relations.—Overlapped by the pectoralis tertius.

Action.—Pulls the coracoid outward. Also aids in keeping the
coracoid in place.

Coraco-brachialis (Fig. 13, No. 15). Location.—Along the cora-
coid shaft.

Origin.—By a delicate tendon from a small circular point on the
postero-mesial part of the shaft of the coracoid immediately above
the attachment of the subclavius and the fossa at that point.

Insertion—To the top of the ulnar tuberosity of the humerus.
This subcircular space is common to the teres minor and to this
muscle. :

Shape.—Long, fusiform.

Relations —With the shaft of the coracoid between the teres
nmainor and subscapularis.

Action.—To depress the wing.

‘ Teres Minor (Fig. 13, No. 14). Location —The coraco-scapular
region.

Origin ~—From under the side of the anterior tip of the scapula.

Insertion.—Passing outward behind the coracoid head and be-

MYOLOGY 103

neath the neck of the scapula, it is attached by a small tendon to
the top of the ulnar tuberosity of the humerus in common with the
coraco-brachialis, with which tendon it fuses.

Shape.—Small, chunky. : '

Relations —Anteriorly, with the tip.of the scapula and behind the
coracoid head. Posteriorly, with the coraco-brachialis.

Action.—Aids in the downward stroke of the wing.

Levator Scapulz. Location —Scapular region.

Origin.—By two strong digitations, one from each of the lateral
processes of the first cervical vertebra.

Insertion.—To the middle third of the inferior part of the blade
of the scapula.

Shape.—Small and flat.

Relations.—Inferior to the scapula.

Action.—Pulls the. scapula forward, and with it the entire shoulder
girdle, which articulates like a hinge-joint at the costo-sternal
juncture.

Thoraco-scapularis. Location.—Lateral side of the chest.

Origin —From the outer part of the lower half of the first free
rib, the outer side of the next succeeding rib and its epineural append-
age, and from a similar surface on the next rib.

Insertion—By a broad, flat tendon. which passes between the
two divisions of the subscapularis and inserts at a point at the
juncture of the anterior and middle third of the outer margin of
the scapula.

Shape.—Broad, flat.

Relations.—Internally, with the ribs and the scapula.

Action.—When the scapula is fixed it is a muscle of inspiration.
When the ribs are fixed, it draws the scapula downward.

Subscapularis. Location.—Scapulo-humeral region.

Origin.—From the anterior and outer-half of the scapula.

Insertion.—By. a strong and subcylindrical tendon to the top of
the ulnar tuberosity of the humerus close to the combined tendons.
of the coraco-brachialis and teres minor. :

Shape—A large and powerful muscle.

Relations.—The flat tendon of the thoraco-scapularis divides the
posterior portion of the belly into two portions.

Action.—A powerful rotary muscle of the head of the humerus;
aids in keeping the humeral head in the glenoid cavity.

104 ANATOMY OF THE DOMESTIC FOWL

THE MUSCLES OF THE BRACHIAL REGION

Biceps Triceps
Deltoid Brachialis anticus

Biceps (Fig. 13, No. 8). (Synonym.—Biceps brachii.)

Location.—The anterior brachial region.

Origin.—By a broad tendon it covers the top of the shoulder-
joint, dividing into two heads, giving rise to the long and the short
heads. The long is inserted into the outer part of the head of the
coracoid just beyond the glenoid cavity; the short head to the
distal angle of the ulnar tuberosity of the humerus.

Insertion.—To the ulna just in front of the articular cavity for
the trochlear surface of the distal extremity of the humerus.

Shape.—Large, subfusiform.

Relations.—On one side by the triceps and the other the deltoid
and anteriorly partially covered by the patagii muscles.

Action.—A powerful flexor of the forearm.

Deltoid (Fig. 13, No. 12; Fig. 15, No. 8). Location.—Occupying
the lateral side of the humerus; the brachial region.

Origin.—Divided into two portions, the long narrow head extends
from the clavicular process of the scapula and from the adjacent
surface of the same bone. These fibers then extend around the back
of the shoulder-joint, and are joined by the fibers that arise from
the entire outer surface of the large os humero-scapulare. These
latter fibers are inserted upon an extensive drea upon the anconal
part of the bone beyond the humeral articular head, and to almost
the entire shaft below it.

Insertion.—By a subcylindrical tendon to the proximal side of the
tubercle of the external condyle, and above the insertion of the
extensor metacarpi radialis longus.

Shape.—Large, fleshy, with tendinous attachment.

Relations —On one side by the biceps and the other by the triceps
also the patagii.

Action—To extend the arm.

Triceps (Fig. 15, No. 7). (Synonym.—Triceps brachii.)

Location.—The posterior humeral region.

Origin.—By three portions: by the internal and external heads,
and by the long scapular head. The internal and the external
heads are blended except at their proximal extremities. Each head’
arises from the anconal surface of the shaft of the humerus. The

“MYOLOGY 105

internal head being located toward the deltoid attachment and the
external head into the pneumatic fossa. ‘The long head extends
from a circumscribed area just posterior to the glenoid cavity of the
scapula. The fibers pass around the shoulder-joint, beneath the
deltoid.

Insertion—The broad tendon passes over the elbow-joint and is
inserted to the entire under surface of the olecranon of the ulna.

Shape—Long, large, fleshy.

Relations.—The supraspinatus passes between the internal and the
external heads. It is bounded by the biceps and the deltoid.

Action.—An extensor of the antibrachial region directly antago-
nizing the biceps.

Brachialis Anticus (Fig. 15, No. 9; Fig. 14, No. 5). Location.—
In the flexure of the humerus and the ulna.

Origin.—It arises fleshy from a circumscribed area on the inner
side of the anconal part of the distal extremity of the humerus.

Insertion.—The fibers passing directly over the elbow-joint become
inserted to the lateral surface of the proximal end of the ulna close
to the margin of the sigmoid cavity.

Shape.—Small, fleshy.

Relations—With the joint.

Action—Assists in flexing the forearm upon the arm. Protects
the structures in the anterior part of the elbow-joint.

THE MUSCLES OF THE FOREARM AND THE HAND

Extensor metacarpi radialislongior Extensor digitorum communis

Supinator brevis Flexor metacarpi radialis
Pronator brevis Pronator longus
Extensor ossis metacarpi pollicis Anconeus

Extensor indicis longus - Flexor digitorum sublimis
Flexor digitorum profundus Flexor.carpi ulnaris

Flexor carpi ulnaris brevior

Extensor Metacarpi Radialis Longior (Fig.13,No.17). Location.—
Superior to the radius.

Origin—By two strong tendinous heads; the outer from the tuber-
cle of the external condyle of the humerus, just above the origin of
the tendon of the tensor patagii brevis; the inner and stronger

106 ANATOMY OF THE DOMESTIC FOWL

portion from the tubercle found above the oblique trochlear facet
of the distal end of the radius.

Insertion Becoming a flat, broad, and strong tendon at about the
middle of the forearm, finally becomes inserted to the apex of the
anchylosed first metacarpal of the carpo-metacarpus.

Shape.—A thick, fusiform belly, tendinous at both extremities.
. Relations—By the side of the pronator brevis.

Action.—Raises the hand, and draws it forward toward the radial
margin of the forearm and retains it-on the same side.

Extensor Digitorum Communis (Fig. 15, No. 2). Location.—The
upper metacarpal region.

Origin—Immediately below the tubercle of the external condyle
of the humerus.

Insertion —By a.small tendon to the outer side of the base of the
polex, and at a mid-point upon the anterior rim of the proximal
phalanx of the middle finger.

Shape.—Small spindle-shaped, becoming tendinous at about the
middle of the forearm. ,

Relations—Occupies the middle of the group of muscles on the
outer side of the forearm.

Action ——An extensor of the digit.

Supinator Brevis (Fig. 14, No. 7). Location —The superior part
of the radius.

Origin.—From the external condyle of the humerus below the
origin of the tendon of the extensor digitorum communis.

Insertion —To the outer side of the shaft of the radius, for nearly
one-third of its length.

Shape.—Thin, slender.

Relations.—Inferiorly, with the bone.

Action.—A supinator of the radial region, and antagonistic to the
pronators.

Flexor Metacarpi Radialis (Fig.15, No. 10). Location.—The low-
est of the group of three muscles on the outer part of the forearm.

Origin.—By two tendinous heads, the longer from the external
condyle of the humerus, and the other just beyond the base of the
olecranon.

Insertion Becomes tendinous at about the middle of the shaft.
of the ulna and inserts to a prominent process on the proximal
third of the posterior part of the shaft of the mid-metacarpal.

Shape.—Fusiform.

MYOLOGY 107

Relations.—Inferiorly, the anconeus and superiorly, the extensor
digitorum communis.
Action.—A powerful flexor of .the hand.
Pronator Brevis (Fig. 13, No. 18). Location.—Supero-lateral
side of the forearm.
. Origin—From just above the internal condyle of the humerus.
Insertion —The tendon passing obliquely across the. interosseous
space and is inserted to the ulnar side of the shaft of the radius,
just beyond the juncture of the proximal and the middle thirds.
Shape.—Fusiform.
Relations.—Superior to the pronator longus.
Action.—Pronates the forearm, and flexes the forearm upon the
arm.
Pronator Longus (Fig. 14, No. 6). Location.—Lateral side of the
radio-ulnar region.
Origin.—From the middle of the internal condyle of the humerus.
Insertion.—To the shaft.of the radius just beneath the pronator
brevis.
Shape.—Massive, ellipsoidal.
Relations —Between the pronator brevis and flexor digitorum
profundus.
Action.—A pronator.
Extensor Ossis Metacarpi Pollicis (Fig. 13, No. 23). Location.—
Slightly interposed between the ulna and radius.
Origin.—Immediately in front of the greater sigmoid cavity of the
ulna.
Insertion-—To the palmar side of the base of the first metacarpal.
in common with the extensor metacarpi radialis longior.
Shape.—Delicate, straight.
Relations.—Superiorly, the extensor indicis longus, and inferiorly,
the anconeus and the flexor digitorum profundus.
Action.— Extends the hand upon the forearm.
Anconeus (Fig. 15, No. 4). Location.—Between the ulna and the
radius.
- Origin.—By a short, strong, subcylindrical tendon from the lower
posterior of the external condyle of the humerus.
Insertion.—To the latero-radial side of the ulna somewhat. beyond
its middle.
Shape.—Fusiform.

108 ANATOMY OF THE DOMESTIC FOWL

Relations.—Superiorly, the extensor indicis longus, and inferiorly,
the ulna.

Action.—A flexor of the forearm.

Extensor Indicis Longus (Fig. 13, No. 22; Fig. 15, No. 13). Lo-
cation.—Infero-lateral to the radius.

Origin.—From about one-half the surface of the proximal portion
of the radius.

Insertion.—Possesses a long tendon which passing over a groove at
the distal end of the ulna and receiving muscular fibers at the base
of the metacarpus, extends down the anterior part of the hand
and is inclosed in a sheath in front of the superior part of the first
phalanx of the index-finger. This tendon is inserted into the an-
terior upper rim of the distal phalanx.

Shape.—Smail, thin.

Relations.—Supero-laterally with the radius.

Action.—Extensor of the digit.

Flexor Digitorum Sublimis. Location—The forearm.

Origin.—From the internal condyle of the humerus.

Insertion Passing over the wrist, it is inserted to the middle
phalanx of the hand.

Shape.—A musculo-tendinous band, rather delicate and rudi-
mentary.

Relations.—Closely adhering to the integument that stretches from
the internal condyle of the humerus to the wrist.

Action——Assists these muscles. A flexor.

Flexor Digitorum Profundus (Fig. 13, No. 21). Location.—
Lateral side of the ulna.

Origin.—By two heads from the proximal extremity of the ulna,
between which the brachialis anticus passes.

Insertion—The two bellies uniting are attached to the under
side of the shaft of the ulna. It becomes tendinous about the middle
of the shaft, and inserts to the ulnar side of the base of the distal
joint of the index-finger.

Shape.—A fleshy belly with long tendon.

Relations.—Inferiorly, with the flexor carpi ulnaris, superiorly,
with the pronator brevis.

‘Action.—A flexor of the digit.

Flexor Carpi Ulnaris (Fig. 13, No. 19). Location.—Inferior part
of the forearm.

Origin.—By two strong tendons; one from the side and posterior

MYOLOGY 109

of the internal condyle of the humerus, passing through the humero-
ulnar pulley at the side of the base of the olecranon process; the
other, to the posterior of the internal condyle of the humerus. It
does not pass through a pulley.

Insertion——A subcylindrical tendon extends back of the ulnare
ossicle of the carpus giving off a tendinous slip to the flexor digi-
torum profundus, and becomes inserted to the anterior rim of the
proximal phalanx of the index digit. It has an attachment at
the carpus.

Shape.—A strong fleshy belly terminating in a long tendon.

Relations —The outermost inferior muscle of the forearm.

Action.—A powerful flexor of the hand upon the forearm.

Flexor Carpi Ulnaris Brevior (Fig. 13, No. 20). Location.—
Inferior part of the antibrachial region.

Origin.—From a broad area on the middle third of the upper side
of the shaft of the ulna. ,

Insertion —Near the top of the outer edge of the anchylosed
os magnum of the carpo-metacarpus.

Shape.—Thin, somewhat flat.

Relations.—To the inside of the flexor digitorum profundus.

Action.—Flexes the hand upon the forearm and rotates the hand
toward the body.

OTHER MUSCLES OF THE DIGITS

Extensor proprius pollicis Flexpr brevis pollicis
Flexor minimi digiti Flexor minimi digiti brevis
Abductor minimi digiti Interosseous dorsalis
Interosseous palmaris Flexor metacarpi brevis

Extensor Proprius Pollicis (Fig. 13, No. 29a). Location. —An-
terior to the radio-carpal joint.

Origin.—From the ulnar side of the tendon of the extensor meta-
carpi radialis longior.

Insertion.—To the antero-ulnar side of the pollex:

Shape.—Small, spindle-shaped; tendinous at both attachments.

Relations.—Inferiorly, with the proximal and anterior part of the
metacarpus. :

Action.—An extensor of the pollex.

Flexor Brevis Pollicis (Fig. 13, No. 28a). Location.—Anterior to

the pollex.

IIo ANATOMY OF THE DOMESTIC FOWL

‘Origin—From the shaft of the mid-metacarpal bone, just below
the pollex.

Insertion.—Distal apex of the pollex.

Shape.—Short, small, fleshy.

Relations.—Superiorly, with the inferior part of the pollex.

Action.—Flexes the pollex.

Flexor Minimi Digiti. Location.—Inferior side of the metacarpus.

Origin.—From the posterior part of the median metacarpal close
to the os carpi ulnare. A few fibers extend to the ulna.

Insertion—Into the base of the median phalanx.

Shape.—Small, slender, short.

Relations.—Superiorly, with the metacarpal bone.

Action.—A flexor of the digit.

Flexor Minimi Digiti Brevis (Fig. 1 3, No. 30). Location.—In-
ferior to the third, or small finger.

Origin.—From the lower and posterior end of the median meta-
carpal and from the adjacent tendon of the preceding.

Insertion Inserted to the apex of the small finger.

Shape.—Small and rather rudimentary.

Relations.—Inferior to the small finger.

Action.—Acts as a posterior ligament of this joint.

Abductor Minimi Digiti. Location—Supero-lateral side of the
small finger.

Origin.—From the proximal extremity of the anterior aspect of the
third finger.

Insertion —To the posterior border of the proximal phalanx of
the second, or index-finger at a point just above the tip of the third
finger.

Shape.—A few muscular fibers with some tendinous material.

Relations —At the base of the median segment of the index-finger
and to the side of the third.

Action.—Antagonizes the powerful flexors on the back of the
joint.

Interosseus Dorsalis (Fig. 13, No. 31). Location—By the side
of the metacarpus. ,

Origin.—From the margin of the shaft of the median metacarpal.

Insertion.—To the anterior pe of the base of the distal phalanz
of the index digit.

Shape.—Short, delicate, with long tendon.

Relations.—Internally, the metacarpal bone.

MYOLOGY Tit

Action.—Extends the last bone of the middle finger.

Interosseus Palmaris (Fig. 13, No. 32). Location.—On the
opposite side of the bone from the interosseous dorsalis.

Origin.—From the shaft of the median metacarpal under the
preceding.

Insertion. —To the apex of the last joint of the second, or middle
finger. rae

Shape.—Small, delicate, with long slender tendon. d

Relations.—Beneath the preceding and along the metacarpal bone.

Action.—Flexes the terminal phalanx.

Flexor Metacarpi Brevis. Location.—To the lateral side of the
metacarpal bone.

Origin.—From the outer side of the distal extremity of the ulna.

Insertion—To the base, in front, and on the ulnar side of the
proximal phalanx of the index digit.

Shape.—Delicate, with long slender tendon.

Relations —On the lateral side of the ulna and the metacarpal
bone.

Action.—Flexes the metacarpus.

MUSCLES OF THE POSTERIOR LIMB

Sartorius Gluteus primus
Gluteus medius Gluteus minimus
Extensor femoris Vastus internus
Biceps flexor cruris Semitendinosus
Semitendinosus accessorius Semimembranosus
Femoro-caudal = - Obturator externus
Obturator internus Gemellus

Abductor longus Adductor magnus

Sartorius (Fig. 23, No. 7). Location—Extreme anterior portion
of the thigh.

Origin.—From the outer two-thirds of the superior surface of the
raised emarginations of the anterior border of the ilium, and by
fascia from the neural spines of the fourth dorsal vertebra.

Insertion.—Obliquely by a semitendinous fascia to the inner edge
of the ligamentum patella, and to the inner and adjacent border of
the anterior half of the summit of the tibia.

Shape.—Large, fleshy.

IiI2 ANATOMY OF THE DOMESTIC FOWL

Relations —Posteriorly, with the gluteus primus and the vasti.

Action Extends the leg, flexes and adducts the thigh.

Gluteus Primus (Fig. 23, No. 8 and 9). Location—The outer
flat massive muscle of the thigh.

Origin.—By a thin fascia from nearly the entire length of the

, Supero-internal margin of the pre-acetabular portion of the ilium,
above the antitrochanter, and from the entire length of the post-
acetabular ridge.

Insertion —Near the patella it joins the tendon of the extensor
femoris, and by aponeurosis spreads over the knee and is inserted
to the crest of the upper border of the tibia, the patella being
incorporated in its aponeurotic ligament.

Shape.—Triangular in shape, it is aponeurotic anteriorly and more
fleshy posteriorly.

Relations.—Anteriorly, covers over the posterior portion of the
sartorius and the body: of the gluteus medius; posteriorly, bordered
by the semitendinosus and the biceps.

Action.—Abducts the thigh.

Gluteus Medius (Fig. 24, No. 11). Location.—Supero-anterior
part of the ilium under the gluteus primus.

Origin —From the entire supero-internal margin of the pre-ace-
tabular surface of the ilium and the concave surface on the adjacent
bone.

Insertion.—By a strong tendon which passes over a bursa on the
anterior rim of the trochanter and is inserted obliquely to this
trochanter.

Shape.—A fleshy muscle filling the concavity of the pre-acetabular
division of the ilium.

Relations.—Superiorly, with the gluteus primus; inferiorly, with
the gluteus minimus.

Action.—Abducts and pulls the femur forward.

Gluteus Minimus (Fig. 24, No. 12). (Synonym.—Gluteus
profundus.)

Location.—Beneath the medius and the smaller of the two.

Origin.—To the anterior margin of the outer border of the ilium,
and from the supero-external surface of the last rib.

Insertion—The fibers extending downward and backward and
outward become tendinous and are inserted below the trochanter
of the outer part of the upper third of the femur.

Shape-——Small, fleshy.

MYOLOGY 113

Relations—Inferiorly, with the bone and superiorly, with the
gluteus medius.

Action.—Abducts and pulls the thigh forward.

Extensor Femoris (Fig. 24, No. 15). Location.—Anterior femoral
region. It is divided into two parts: the vastus externus and the
crureus.

Origin.—The vastus externus (Fig. 24, No. 14) arises tendinous
from the base of the trochanter of the outer part of the femur and
from this point down the bone approximately to the condyle.
The crureus (Fig. 24, No. 13) originates by a tendon from
the anterior upper prominent rim of the trochanter, from this
point extending down the ai tero-external part of the shaft of the
femur.

Insertion—Merges with the gluteus primus,.and, by a fascia-like
arrangement, spreads over the front of the knee-joint inserts to the
patella and is also inserted into the crest of the tibia.

Shape.—Large, fleshy.

Relations —Posteriorly, with the femur and anteriorly, with the
‘sartorius.

Action.—Extends strongly the leg upon the thigh.

Vastus Internus (Fig. 16, No. 3). Location.—Internal and lateral
side of the femur.

Origin.— From the postero-internal part of the shaft of the femur
just below the head, and in a straight line extending down the femur.

Insertion —By a broad tendon aldng the thickened inner border
of the summit of the tibia.

Shape.—Thick, long. _

Relations.—Anteriorly, with the bone; surrounded by the other
crural muscles.

Action.—Extends the leg upon the knee; a powerful assistant of
the extensor femoris.

Biceps Flexor Cruris (Fig. 17, No. D, 1). Location. —Posterior
tibial region.

Origin—By a tendinous fascia from the post-acetabular ridge,
extending between the antitrochanter and the anterior point of the
insertion of the semitendinosus.

Insertion.—To the tuberosity on the external part of the shaft of
the fibula a short distance below the head.

Shape.—Large, rather cone-shaped with base directed upward.

Relations.—Anteriorly, with the vastus externus; posteriorly, with
8

II4 ANATOMY OF THE DOMESTIC FOWL

the semitendinosus. The inferior tendinous portion passes through
a tendinous sling or pulley called the biceps band. :

Action.—Flexes the leg upon the thigh. :

Semitendinosus (Fig. 23, No. 10). Location.—Posterior femoral
region.

Origin —By a tough, strong fascia from the surface of the caudal
muscles and from the posterior third of the post-acetabular ridge.

Insertion —The fibers pass downward and forward, and insert to
the tendinous raphe along the posterior margin of the semitendinosus
accessorius; lower down it merges with the median fascia of the
inner head of the gastrocnemius.

Shape.—Fleshy, broad, flat and long.

Relations.—Internally, with the semimembranosus and anteriorly,
with the biceps flexor cruris.

Action.—F lexes the leg.

Semitendinosus Accessorius. Location—Posterior femoral region.

Origin—From an oblique line just above the condyle, on the
posterior of the shaft of the femur.

Insertion.—Its fibers, passing upward and backward, attach them-
selves to the tendinous raphe common to this muscle and the semi-
tendinosus, and are finally inserted to the inner side of the shaft of
the tibia.

Shape.—Flat, oblong.

Relations.—Posteriorly to the shaft of the femur, and externally
to the long adductors of the thigh.

Action.—Aids the preceding in flexing the leg.

Semimembranosus (Fig. 24, No. 17). .Locatton.—Postero-internal
to the semitendinosus.

Origin.—From the outer surface of the ischium, beginning at the
lower margin of its notch on the posterior pelvic border, extends on
a curved line on the adjacent surface beyond.

Insertion.—The fibers, passing downward and forward, insert by a
broad, thin tendon to the shaft of the tibia a short distance below
the head and on a line parallel to the long axis of the tibia.

Shape.—Long, narrow, ribbon-shaped.

Relations.—Lies adjacent to the semitendinosus and in the same
plane. ;

Action.—Directly flexes the leg.

Femoro-caudal (Fig. 24, No. 8). Location—Infero-lateral to
the caudal and post-femoral region.

MYOLOGY 115

Origin.—By a delicate tendon from the base of the pygostyle.

Insertion.—By a thin, flat tendon upon the outer part of the shaft
of the femur below the trochanter and at about the juncture of the
upper and middle third of the bone.

re

Fic. 24.—Second layer of muscles of the thigh of a cock. Outside view. 1,
Appendico-costales. 2, Levatores costarum. 3, Sacro-lumbalis. 4, Longissi-
mus dorsi. 5, Intercostales. 6. Longissimus dorsi. 7, Latissimus dorsi. 8,
Femoro-caudal. 9, Edge of obturator externus. 11, Gluteus medius. 12,
Gluteus minimus. 13, Crureus. 14, Vastus externus. 15, Extensor femoris.
16, Biceps flexor cruris. 17, Semimembranosus. 18, Adductor magnus. 19,
Adductor longus. 20 External abdominal oblique. 21, Depressor coccygis.
22, Tibialis anticus. 23, Tibialis posticus. 24, Flexor perforans digitorum pro-
fundus. 25, Flexor perforatus medius secundus pedis. 26, Flexor longus
hallucis.

Shape.—Long, narrow, spindle-shaped, flattened from side to side.

Relations.—Inferiorly to the obturator externus, and along the
upper border of the long adductors of the thigh and the semi-
membranosus. ,

Action.—Pulls the tail down and to one side.

116 ANATOMY OF THE DOMESTIC FOWL

Obturator Externus (Fig. 24, No.9). Location.—External postero-
lateral side of the pelvis.

Origin.—From the posterior half of the periphery of the ischiatic
foramen and the concavity found on the external surface of the
lateral part of the pelvis.

Insertion—The fibers pass across to the femur and are inserted
by a broad, flat tendon to the shaft of the femur just below the
trochanter. :

Shape—Thick, fleshy.

Relations.—Lies just above the femoro-caudal muscle, the sciatic
nerve and femoral artery pass over and external to its tendon.

Action.—Pulls the head of the femur backward.

Obturator Internus (Fig. 16, No. E, 1). Location.—Occupies the
space between the ischium and the pubis.

Origin.—From the ventral surface of the ischium, including the
posterior border, from the inner line of the corresponding post-
pubis, and from the membrane covering the space between these
two bones.

Insertion—Becoming dense, subcylindrical, and strong, it passes
through the obturator foramen and is inserted to the outer part of
the trochanter of the femur, in common with the gemellus and
opposite to the insertion of the gluteus medius.

Shape.—Subtriangular and flat with a central tendon; bipenni-
form.

Relations.—Outside the pelvis the tendon lies upon the gemellus
and is external to it. Fills the obturator foramen and the space
between the ischium and the pubis.

Action.—Acts as a posterior stay to the head of the femur.

Gemellus (Fig. 25, No.5). Location.—Posterior to the head of
the femur.

Origin.—From the fossa between the acetabulum and the obtura-
tor foramen, and on the outer side of the pelvis.

Insertion.—Its fibers are attached by fascia to the tendon of the
obturator internus, and pass directly to the trochanter of the femur
where they insert in common with that of the obturator internus.

Shape.—Strong, thick, chunky.

Relations.—Postero-external to the head of the femur.

Action.—Like the two preceding, when the head of the femur is
fixed, it pulls the pelvis forward and steadies it on the head of the
femur.

\
\.

MYOLOGY Thy

Adductor Longus (Fig. 24, No. 19). Location.—In the posterior
femoral region.

Origin.—From a line on the lateral part of the pelvis.

Insertion.—The fibers, passing downward and forward, are in-
serted on a longitudinal line along the posterior part of the shaft of
the femur.

Shape.—Broad, flat, fleshy.

Relations. —Posteriorly to the femur, and anteriorly to the adduc-
tor magnus.

Action.—Adducts the thigh.

Adductor Magnus (Fig. 24, No. 18). Location.—Posterior femoral
region.

Origin.—From the line constituting the lower boundary of the
ischiatic fossa on the outer lateral part of the pelvis.

Insertion—The fibers pass downward and are inserted to
the superior curve of the internal femoral condyle. The internal
head of the gastrocnemius blends with this muscle just above its
attachment.

Shape.—Long, narrow.

Relations.—Posteriorly to the adductor magnus and anteriorly
to the semimembranosus.

Action.—Strongly adducts the thigh.

THE TIBIAL GROUP

Gastrocnemius Tibialis anticus
Peroneus longus Extensor hallucis brevis
Extensor longus digitorum Flexor perforatus indicis
Tibialis posticus secundus pedis
Flexor longus hallucis Flexor perforatus medius
Flexor perforatus annularis primus primus pedis

pedis Flexor perforatus indicis
Flexor perforatus medius secundus primus pedis

pedis Extensor brevis digitorum
Flexor perforans digitorum pro- Flexor hallucis brevis

fundus Extensor annularis brevis
Soleus

Gastrocnemius (Fig. 23, No. 11). Location.—Posterior tibial
region.

118 ANATOMY OF THE DOMESTIC FOWL

Origin.—There are three heads: the internal, the external, and
the tibial. The external head extends by a short, flattened, strong
tendon from the postero-external part of the external condyle of
the femur; the internal head extends from the outer surface of the
inner condyle of the femur; and the tibial head extends from the
entire inner rim of the tibial summit and from the free edge of the
adjacent crest.

Insertion—At the lower fourth of the tibial shaft, terminates in
a broad, flat tendon which passes over the shallow, longitudinal
groove of the tibial cartilage, and, crossing the tibio-tarsal joint,.
is inserted to the posterior surface of the hypotarsus of the metatarsal
bone, and finally, below this point, merges into the podothecal

Sheath confining the flexor tendons.

Shape.—Large, fleshy, somewhat cone-shaped with the base
upward.

Relations.—The posterior fleshy muscle of the post-tibial region
located anterior to the soleus.

Action ——Extends the metatarsus on the tibia.

Soleus (Fig..25, No.G,1). Location.—The posterior tibial region.

Origin.—From the posterior part of the head of the tibia.

Insertion—By a long slender tendon to the proximal end and
toward the inner angle of the tibial cartilage, some of the fibers
passing to the tendon of the gastrocnemius.

Shape.—Small, flattened.

Relations —Anteriorly, with the flexor perforans digitorum pro-
fundus and posteriorly, with the gastrocnemius.

Action.—Similar to that of the gastrocnemius.

Peroneus Longus (Fig. 23, No: 12). Location —Antero-lateral
tibial region.

Origin.—From the raised crest in front of the head of the tibia,
and from the fascia that covers the outer side of the knee-joint.

Insertion —The fibers, passing downward, then downward and
outward, terminate in a small tendon.at the lower third of the tibia.
This tendon bifurcates just above the tibial condyles at the outer
part of the limb, the shorter and stronger attaches to the fibrous
fascia covering the tibial cartilage, the other merging’ with the
tendon of the flexor perforatus medius primus pedis about 1 cen-
timeter below the hypotarsus of the tarso-metatarsus.

Relations—Covers over all the muscles of the anterior tibial
region.

MYOLOGY TIQ

Shape.—A broad muscular sheet.

Action.—Assists the flexor perforatus medius primus pedis.

Tibialis Anticus (Fig. 24, No. 22). Location —In the anterior
tibial region.

Origin.—The muscular belly may be easily divided into two parts.
The inner-head extends from the head of the tibia immediately
beneath the: peroneus longus. The outer head arises by a strong
tendon from a depression on the antero-inferior ridge of the outer
condyle of the fernur.

Insertion.—The tendon passing through the fibrous ligamentous
loop just above the tibial condyles, inserts to a tubercle on the
shaft just below the head of the tarso-metatarsus.

Shape.—Large, fusiform.

Relations —Beneath the peroneus longus.

Action.—Flexes the metatarsus upon the tibia.

Extensor Longus Digitorum (Fig. 25, No. G, 6). Location —-An-
terior tibial region.

Origin.—From the inferior portion of the crest and a portion of
the shaft of the fibula.

Insertion——It becomes tendinous at the lower third of the bone,
passing under the bony ridge just above the condyle in front,
and over the ankle-joint. It is bound down by firm fascia, and at
the trochlea of the basal toe joints, divides into three small tendin-
ous slips. These pass over the superior part of the second, the
third, and the fourth toes, bifurcating in their course, and are
inserted to the distal ones.

Shape.—Long, penniform, with a long, slender tendon.

Relations.—Immediately below the tibialis anticus.

Action.—Extends the digits as their long extensor.

Extensor Hallucis Brevis (Fig. 25, No. G, 4). Location—The
anterior metatarsal region, along the antero-internal edge.

Origin.—From just below the summit of the antero-internal part
of the head of the tarso-metatarsus, and from the adjacent shaft
below, and from the tendon of the tibialis anticus.

Insertion.—Into the process at the superior part of the bone of
the bony claw of the hallux.

Shape.—Slender, thin in diameter, with a long, slender tendon.

Relations.—Superiorly, with the antero-internal edge of the
metatarsus and inferiorly, its tendon with the top of the hallux.

Action.—Extends the hallux.

‘120 ANATOMY OF THE DOMESTIC FOWL

Extensor Brevis Digitorum. Locafion.—On the anterior surface
of the metatarsus.

Fic. 25.—Inner layer of muscles of the thigh of a hen. Outside view.

A. Pad of fibrocartilage or meniscus of femoro-tibial articulation. 1, Inner
semilunar fibrocartilage. 2, External semilunar cartilage. 3, Anterior border.

B. Tarsal meniscus or pad of fibrocartilage. __

C. Articular surface of the tarsal joint. 1, Posterior ligamentum cruciatum
genu. 2, Femoral tendinous insertion of tibialis anticus. 3, Ligamentum tibio-
fibulare. 4, Ligamentum interosseum. 5, Ligamentum transversum of the
meniscus. 6, Anterior ligamentum cruciatum genu.

D. 1, Tibia. 2, Fibula. 3, Femur. 4, External ligamentum laterale genu.

E. Inferior surface of the tail of ahen. 1, Infracoccygis. z, Lateralis coccy-

s.
F. Outside pelvic view. 1, Obturator ligament. 2, Tendon of the obturator
internus. 3, Ligamentum oblongum. 4, Ligamentum capsulare. 5, Gemellus.
G. Outside view of leg of a cock. 1, Soleus. z, Flexor longus hallucis. 3,
Flexor perforans digitorum profundus. 4, Extensor brevis hallucis. 5, Extensor
brevis annularis. 6, Extensor longus digitorum. 7, Tendon of the tibialis

posticus. .
H. 1, Transversalis abdominalis. , Cotyloid cavity.

Origin.—By a small fleshy belly to the anterior part of the
proximal end of the metatarsus.

Insertion.—It becomes tendinous about the middle third of the
metatarsus. Extending down theanterior face of the metatarsusitis

‘

MYOLOGY 121

inserted to the inner tubercle of. the base of the first phalanx of
the outer or fourth toe.

Shape.—Long, slender.

Relations.—Posteriorly with the metatarsus.

Action.—Pulls the fourth toe upward and inward.

Flexor Hallucis Brevis. Location.—Postero-internal side of the
metatarsus.

Origin.—Side and lower margin of the inner aspect of the hypo-
tarsus of the tarso-metatarsus and from the shaft of this bone
immediately below it.

Insertion.—Winds round inner side of basal joint of the hallux
and is inserted on its under side.

Shape.—Small flat muscle gradually tapering into a tendon.

Relations.—Posteriorly with the metatarsus.

Action.—To flex the hallux.

Extensor Annularis Brevis. Location.—On postero-external side
of metatarsus.

Origin.—External aspect of the hypotarsus and the shaft below.

Insertion —Supero-external part of the basal phalanx of the
fourth toe.

Shape.—Small flat muscle.

Relations.—Posteriorly with the metatarsus.

Action.—Extensor of the fourth toe.

Tibialis Posticus (Fig. 24, No. 23). Location.—In the posterior
tibial region. o

Origin.—From the whole shaft of the fibula below the insertion
of the biceps flexor cruris, and from the shaft of the tibia a short
distance below this insertion. Also from the interosseous mem-
brane, and the adjacent surface of the tibial shaft.

Insertion.—Passing in front of the external malleolus, crossing the
ankle-joint, finally inserted into the outer edge of the summit of
the tarso-metatarsal bone.

Shape.—Long, subcylindrical.

Relations —Medially, with the flexor perforans digitorum pedis;
superiorly, with the postero-external portion of the tibia.

Action.—Extends the metatarsus upon the tibia.

Flexor Perforatus Indicis Secundus Pedis (Fig. 17, No. 5). Loca-
tion.—The posterior tibial region.

Origin.—From the external surface of the outer condyle of the
femur, just below the head of the gastrocnemius.

122 ANATOMY OF THE DOMESTIC FOWL

vf nsertion.—Passing in an oblique manner along posterior to the
tibia, extends through the superficial part of the tibial cartilage to
the outer side of the leg; then crossing the tibio-tarsal joint, it
passes through a special canal of the hypotarsus, down the back
of the tarso-metatarsus, under the annular ligament of the sole of
the foot and a cartilaginous structure below this ligament, over
the trochlea, and is inserted to the middle shaft of the second
phalanx of the second toe.

Shape.—Thin, flat, broadly spindle-shaped.

Relations—Posteriorly, with the flexor perforatus medius secun-
dus pedis, and anteriorly, with the flexor perforatus annularis
primus pedis.

Action.—Flexes the toes.

Flexor Longus Hallucis (Fig. 17, No. 7; Fig. 25, No. 2). Loca-
tion.—The posterior tibial region.

Origin.—By two tendinous heads: one from the posterior part of
the femur, just below the two condyles; the other from the outer
part of the external condyle of the femur. The deep flexor passes
between these two heads.

Insertion.—Becoming tendinous at the lower third of the leg,
passes beneath the superficial flexors in a special canal on the outer
side of the tibial cartilage, and extends through the large canal of
the hypotarsus (Fig. 12, No. F, 5) next to the shaft, then down to
the apex of the accessory metacarpal bone. It is inserted to the
tubercle on the inferior proximal end of the ungual phalanx.

Shape.—Large, fusiform.

Relations.—With the exterior of the deep flexors.

Action.—Flexes the hallux as its long flexor.

Flexor Perforatus Annularis Primus Pedis (Fig. 17, Nos. D, 8
and C, 6). Location—The posterior tibial region.

Origin.—From the inner side of the belly of the flexor longus
hallucis.

Insertion Becoming tendinous at the lower third of the tibia,
passes a little to the outer side and through the tibial cartilage,
then over the ankle-joint and through the hypotarsal canal (Fig.
12, No. 5) to the under side of the outer toe, where it forms a sheath
through which the deep flexors extend. It gives off on either side
a tendinous slip which attaches to the basal phalanx.

Shape.—Long, slender, compressed laterally.

MYOLOGY. 123

Relations.—Internally, with the flexor perforatus indicis secundus
pedis, and externally, with the flexor longus hallucis. :

Action.—Flexes the toes as their long flexor. A second flexor of
the outer toe.

Flexor Perforatus Medius Secundus Pedis (Fig. 17, No. 9).
Location.—The posterior tibial region.

_ Origin —From a strong fascia that merges with the knee-joint,
and by a tendon from the external condyle of the femur in common
with the tendon of the flexor perforatus indicis secundus pedis.

Insertion—Continued as a flattened tendon extending from the
lower third of the leg, passing obliquely through the tibial cartilage
and then through the interno-posterior canal of the hypotarsus,
(Fig. 12, No. F, 5) inserted to the second joint of the middle toe.

Shape.—Long, fusiform.

Relations —With the shaft of the fibula, which it covers.

Action.—Flexes the middle toe.

Flexor Perforatus Medius Primus Pedis (Fig. 17, No. 2). Loca-
tion.—Posterior tibial region.

Origin.—From the inner side of the muscular portion of the flexor
perforatus annularis primus pedis.

Insertion.—Terminating in a flattened tendon, passes through
the tibial cartilage and hypotarsus, and then extends along the
shaft of the basal joint of the third toe, and, dividing into two
slips, inserts to either side of its shaft.

Shape.—Long, rather small.

Relations.—With the flexor perforatus annularis primus pedis
on the inner side. -

Action.—Flexes the third toe.

Flexor Perforatus Indicis Primus Pedis (Fig. 17, No. 4). Loca-
tion.—The posterior tibial region.

Origin.—From a thin, broad tendon, on the external condyle of
the femur, in common with the flexor perforatus medius secundus
pedis.

Insertion Becoming tendinous, passes through the tibial cartilage
and the hypotarsus of the metatarsus (Fig. 16, A) and inserts
to the sides of the basal joint of the second toe.

Shape.—Long, slender, fusiform; somewhat flattened laterally.

Relations—With the flexor perforatus medius secundis pedis,
posteriorly.

Action.—A flexor of the toes.

I24 ANATOMY OF THE DOMESTIC FOWL

Flexor Perforans Digitorum Profundus (Fig. 24, No. 24 and
Fig. 25, No. G, 3). Location.—The posterior tibial region.

Origin.—From the posterior part of the external condyle of the
femur, from the posterior part of the tibia just below the summit,
and from a point near the origin of the soleus.

Insertion.—Its heavy flattened tendon passes through the tibial
cartilage, this tendon dividing, the branches pass along the under
side of the toes, perforating the outer tendons and become inserted
to the proximal tubercle at the base of the under side of the ungual
phalanxes of the second, third, and fourth toes.

Shape.—Long, fleshy, with a long tendon.

Relations —Closely with the tibial bone; the deepest of all the
flexors.

Action.—Flexes the digits.

THE MUSCLES OF THE EYE

Orbicularis palpebrarum Levator palpebre su-
perioris

Depressor palpebra inferioris Quadratus nictitans!

Pyramidalis nictitans Obliquus superior.

Obliquus inferior Rectus superior

Rectus inferior Rectus externus

Rectus internus

Orbicularis Palpebrarum (Fig. 7, No. 30). (Synonym.—Orbicu-
laris oculi.)

Location.—Upon the lacrimal and maxillary bones.

Origin.—From the lacrimal and maxillary bones and the ciliary
margin.

Insertion —To the lower free edge of the tarsal cartilage.

Shape.—Thin, delicate layer of fibers.

Relations —Externally, with the skin; internally, with the lacri-
mal and the maxillary bones.

Action.—Aids in closing the eye.

Levator Palpebrze Superioris (Fig. 7, No. 24). Location—Along
the superior roof of the orbit.

Origin.-—Along a longitudinal line found near the middle of the
roof of the orbit.

MYOLOGY 125

Insertion —To the ciliary margin of the upper lid, near the outer
canthus.

Shape.—Thin, delicate layer.

--- Relations.—Superiorly, with the bony wall, and inferiorly, with the

eyeball.

Action.—Raises the superior eyelid.

Depressor Palpebre Inferioris (Fig. 7, No. 29). (Synonym.—
Malaris.)

Location.—Along the inferior border of the eye.

Origin.—From the inferior border of the interorbital foramen.

Insertion ——To the lower lid.

Shape.—Thin, flat, delicate.

Relations —Superiorly, with the eyeball; inferiorly, with the
inferior orbital wall.

Action.—Pulls the lower lid down.

Quadratus Nictitans (Fig. 26, No. B, 7). Location—Above the
eyeball along the inferior border of the upper wall of the orbit.

Origin.—From the sclerotic from the upper part of the ball.

Insertion:—To the upper part of the sheath of the optic nerve near
the optic foramen.

Shape.—Broad, thin, quadrate.

Relations —Inferiorly, with the eyeball; superiorly, with the
orbital wall, with the superior oblique, and with the superior rectus.

Action.—Aids in pulling the nictitating membrane obliquely out-
ward and downward over the forepart of the eyeball.

Pyramidalis Nictitans (Fig. 26, No. B, 8). Location.—Infero-
posteriorly to the eyeball.

Origin —From the lower nasal side of the eyeball.

Insertion—The fibers converge toward the upper part of the
optic nerve, into a tendon which passes through a pulley at the
free margin of the quadratus. Inserts to the lower part of the
margin of the third eyelid, the nictitans.

Shape.—Pyramidal; of thin layers of fibers.

Relations.—Internally, with the bony orbital wall; externally,
with the eyeball.

Action.—Aids the quadratus nictitans.

Obliquus Superior (Fig. 26, No. B, 5). (Synonym.—Obliquus
dorsalis.)

Location—Superior to the eyeball.

126 ANATOMY OF THE DOMESTIC FOWL

Fic. 26.—Structures of the eye and nasal passage.

A. 1, The anterior turbinated bone. 2, The posterior turbinated bones. 3,
Orbital gland. 4, Ophthalmic division of the fifth pair of cranial nerves. 5,
Section through the cerebrum. 6, Section through the skull showing the air
spaces. 7, Section through the comb. 8, Anterior portion of the upper beak.
9, Edge of the hard palate.

B. The intrinsic muscles of the eyeball. 1, Superior rectus. z, Internal
rectus. 3, Inferior rectus. 4, External rectus. 5, Superior oblique. 6, In-
ferior oblique. 7, Quadratus. 8, Pyramidalis. 9, Optic nerve. 10, Edge of
membrana nictitans.

C. Posterior part of the eye showing at the inferior portion of the ball the
pyramidalis muscle at 1, and at 2, the quadratus. 3, Optic nerve.

D. Inner view of the posterior part of the vitreous chamber. 1, Sclerotic
coat. 2, Choroid coat. 3, Retina. 4, Pecten. :

'E. Longitudinal section through the eye of a hen. 1, Cornea. z, Anterior
chamber. 3, Scleral ring. 4, Crystalline lense. 5, Iris. 6, Retina. 7, Scler-
otic. 8, Choroid. 9, Pecten. 10, Optic nerve. 11, Vitreous chamber.

F. An edge view of the crystalline lense of a hen showing it to be asymmetrical
biconvex. 1, The anterior side. 2, The posterior side.

G. The upper section through the anterior portion of the anterior turbinated
bone showing one complete circle and the lower a section through the middle
turbinated showing one and one-half turns.

MYOLOGY iy

Origin —From the orbital septum just back of the inner canthus,
the fibers passing backward and forward.-

Insertion.—Into the sclera, anterior to the sclerotic plate

Shape.—Small, thin, fan-shaped.

Relations —With the eyeball, superiorly; at its extremities with
the superior rectus, interiorly.

Action.—Rotates the eyeball.

Obliquus Inferior (Fig. 26, No. B, 6). (Synonym.—Obliquus
ventralis.)

Location.—Inferior to the eyeball.

Origin.—From the interorbital septum near the inner canthus
of the eye.

Insertion—By a broad expansion to the inferior portion of the
eyeball.

Shape.—Tendinous at its insertions; fan-shaped as it passes down-
ward and outward.

Relations.—Internally, with the eyeball; and externally, with the
bony orbital wall, with the inferior rectus muscle, inferiorly.

Action.—Aids in rotating the eye; opposes the obliquus superior.

Rectus Superior (Fig. 26, No. B,1). (Synonym.—Rectus dorsalis.)

Location.—Superior to the eyeball.

Origin.—Along the supero-posterior border of the optic foramen.

Insertion.—To the sclera just within the margin of the bony circle
of the eye.

Shape.—F lat, thin.

Relations.—Internally, with the obliquus superior; superiorly,
with the bony wall of the orbit.

Action.—To pull the eyeball upward.

Rectus Inferior (Fig. 26, No. B, 3). (Synonym —Rectus ventralis.)

Location.—Inferior to the eyeball.

Origin.—From the inferior border of the optic foramen.

Insertion.—To the lower portion of the eyeball within the margin
of the bony circle of the eye.

Shape.—Thin, fan-shaped.

Relations —Superiorly, with the eyeball; inferiorly, with the
bony wall of the orbit.

Action.—Pulls the eyeball downward.

Rectus Externus (Fig. 26, No. B, 4). (Synonym.—Rectus
lateralis.)

Location.—External to the eyeball.

128 ANATOMY OF THE DOMESTIC FOWL

Origin.—By two heads infero-laterally to the optic foramen.

Insertion.—To the postero-external side of the eyeball.

Shape.—Short, fan-shaped.

Relations.—Internally, with the eyeball; externally, with the bony
wall of the orbit.

Action.—Pulls the eyeball outward.

Rectus Internus (Fig. 26, No. B, 2). (Synonym.—Rectus
medialis.)

Location.—Inner side of the eyeball.

Origin.—From the supero-anterior border of the optic foramen.

Insertion.—To the sclera on the anterior portion of the eyeball.

Shape.—Thin, fan-shaped.

Relations.—Internally, with the eyeball and with the pyramidalis;
externally, with the bony wall of the orbit.

Action.—Pulls the eyeball inward.

THE MUSCLES OF THE EAR

Circumconcha Tensor tympani

Circumconcha (Fig. 7, No. 32). Location Surrounds the exter-
nal ear. ,

Origin and Insertion.—The circumconcha, surrounding the periph-
ery of the ear, is adherent to the skull and loosely to the skin, and
is attached to the outer terminus of the supra-occipital crest.

Relations.—Internally, with the skull; externally, with the skin.

Action.—Relaxes the tympanum.

Tensor Tympani (Fig. 7, No. 31). Location.—External to the
quadrate and to the external auditory meatus.

Origin and Insertion.—From the surface of the quadrate and the
inner end of the quadrato-jugal to the inner surface of the tympanum.

Shape.—A few fibers.

Relations.—Internally, with the quadrate and the quadrato-jugal;
externally, the integumental duplicature.

Action.—Tenses the tympanum.

FUNCTIONS OF MUSCLES

To cause the feathers on the top of the head to lie flat:
Dermo-frontalis.
To raise the feathers along the superior part of the neck and along the dorsal
region:
Dermo-dorsalis.

MYOLOGY 129

To tense the patagial region:
Dermo-tensor patagii,
Dermo-temporalis.
To cause the feathers to lie close to the body:
Dermo-humeralis,
Dermo-pectoralis.
To tense the lateral cervical integument:
Dermo-temporalis.
To support the lingual apparatus and superior larynx:
Platysma myoides.
To manipulate the feathers and skin of the inferior part of the neck:
Cleido-trachealis.
To control the skin in the shoulder region:
Dermo-spinalis.
To cause the feathers of the back to lie close to the skin:
Dermo-iliacus.
To depress the humeral region:
Dermo-ulnaris.
To close the jaw:
Temporalis,
Pterygoideus internus,
Pterygoideus externus,
Masseter.
To open the jaw:
Biventer maxilla,
Entotympanic.
To raise the trachea and hyoid apparatus:
Digastricus.
To elevate the tongue:
Mylo-hyoideus.
To pull the tongue to one side:
Singly—
Cerato-hyoideus,
Stylo-hyoideus.
Alone when the larynx is fixed—
Sterno-hyoideus.
Those which protrude the tongue from the mouth:
Together—
Cerato-hyoideus
Genio-hyoideus.
To aid in deglutition:
When the base of the tongue is fixed—
Sterno-hyoideus.
To depress the tongue:
Together—
Sterno-hyoideus.

,

1 Muscles are arranged in pairs. Singly means one muscle acting alone, i.e.,
without its fellow; together means acting both at the same time.
9

130 ANATOMY OF THE DOMESTIC FOWL

To depress the tip of the tongue and elevate the base:
Depressor glottis.
To elevate the hyoid arches:
Cerato-glossus.
To extend the head:
Complexus,
Rectus capitis anticus minor,
To flex the head upon the neck:
Flexor capitis inferior.
To extend the head on the neck and elevate the neck:
Biventer cervicis.
To raise the neck upward:
Longus colli posticus.
To flex each vertebra on the preceding or succeeding laterally:
Obliquus colli,
Intertransversales.
To pull the neck downward:
Longus colli anterior.
To pull the head downward:
Together—
Rectus capitis lateralis,
Trachelo-mastoideus.
To pull the head downward and to one side:
Singly—
Rectus capitis lateralis,
Trachelo-mastoideus.
To approximate the spinous processes of the vertebre.
Interspinales.
To approximate the vertebre in a supero-lateral direction:
Interarticulares.
To flex the vertebra supero-laterally:
Obliquo-transversales.
To extend the neck:
Together when the first rib is fixed—
Scalenus medius.
To close the glottis:
Constrictor glottidis.
To open the glottis:
Thyreo-arytenoideus.
To approximate the tracheal rings:
Tracheo-lateralis.
To tense the inferior larynx:
Broncho-trachealis posticus,
Broncho-trachealis anticus
Broncho-trachealis brevis,
Bronchialis posticus,
Bronchialis anticus.

MYOLOGY

To relax the inferior larynx:

Sterno-trachealis.

To aid in respiration:

When the first rib is fixed—
Intercostales.

When wing is fixed—
Latissimus dorsi,
Dermo-cleido dorsalis.

When the scapula is fixed—
Serratus magnus anticus,
Serratus parvus anticus,
Thoraco-scapularis,
Levatores costarum,
Appendico-costales,
Triangularis sterni.

To flex the shoulder-joint:

Latissimus dorsi.

To elevate the humerus:

Latissimus dorsi.

To draw the scapula forward:

Trapezius,

Rhomboideus.

To close the wing:

Teres et infraspinatus.

To extend the humerus:

Coraco-humeralis,

Scapulo-humeralis.

To pull the humerus upward and backward:

When the scapula is fixed—
Supraspinatus.

To pull the coracoid outward:
Subclavius.

To depress the wing:
Coraco-brachialis.

To depress the scapula:
When the ribs are fixed—

Thoraco-scapularis.

-To rotate the humerus:
Subscapularis.

To flex the forearm:
Pronator brevis,
Biceps,
Brachialis anticus,
Anconeus,
Tensor patagii longus,
Tensor patagii brevis.

To extend the arm:
Deltoid.

131

132 ANATOMY OF THE DOMESTIC FOWL

To extend the antibrachial region:
Triceps.
To raise and to draw the hand forward:
Extensor metacarpi radialis longior.
To extend the digit:
Extensor indicis longus,
Extensor digitorum communis,
Extensor proprius pollicis,
Interosseous dorsalis.
To supinate the radial region:
Supinator brevis.
To flex the hand:
Flexor metacarpi radialis.
To pronate the forearm:
Pronator brevis,
Pronator longus.
To extend the hand on the forearm:
Extensor ossis metacarpi pollicis.
To flex the digit:
Flexor minimi digiti,
Flexor digitorum sublimis,
Flexor brevis pollicis,
Flexor digitorum profundus,
Interosseous palmaris.
To flex the hand upon the forearm:
Flexor carpi ulnaris,
Flexor carpi ulnaris brevior.
To rotate the hand toward the body:
Flexor carpi ulnaris brevior.
To abduct the digits:
Abductor minimi digiti.
To flex the metacarpus:
Flexor metacarpi brevis.
To extend the leg:
Sartorius.
To adduct the thigh:
Sartorius,
Adductor longus,
Adductor magnus.
To abduct the thigh:
Gluteus primus,
Gluteus medius,
Gluteus minimus.
To pull the thigh forward:
Gluteus minimus,
Gluteus medius.
To extend the leg upon the thigh:
Extensor femoris,

MYOLOGY 133

Vastus internus.
To extend the leg upon the knee:
Vastus internus.
To flex the leg upon the thigh:
Biceps flexor cruris,
Semitendinosus,
Semitendinosus accessorius,
Semimembranosus.
To pull the tail down and to one side:
Femoro-caudal.
To pull the head of the femur backward:
Obturator externus.
To act as a posterior stay to the head of the femur:
‘Obturator internus.
To pull the pelvis forward and to steady it on the head of the femur:
Gemellus,
Obturator internus,
Obturator externus.
To extend the metatarsus on the tibia:
Gastrocnemius,
Soleus,
Tibialis posticus.
To flex the toes:
Peroneus longus,
Flexor perforatus medius primus pedis,
Flexor perforatus indicis secundus pedis,
Flexor perforatus medius secundus pedis,
Flexor perforatus indicis primus pedis,
Flexor perforans digitorum profundus,
Flexor longus hallucis,
Flexor perforatus annularis primus pedis.
To flex the metatarsus on the tibia:
Tibialis anticus.
To extend the toes:
Extensor longus digitorum,
Extensor hallucis brevis.
To flex the back laterally and to aid in raising the body.
Sacro-lumbalis,
Longissimus dorsi.
To elevate the tail:
Levator coccygis,
Levator caude.
To depress the tail:
Depressor caudz,
Infracoccygis.
Together—
Depressor coccygis,
Lateralis caude.

134 ANATOMY OF THE DOMESTIC’ FOWL

To pull the tail down ward and to one side:
Singly—
Lateralis coccygis.

Depressor coccygis,
Lateralis caude.

To close the eyelids:
Orbicularis palpebrarum.

To raise the superior eyelid:
Levator palpebre superioris:

To pull the lower eyelid downward:

_ Depressor palpebrz inferioris.

To pull the membrana nictitans over the eyeball:
Quadratus nictitans,
Pyramidalis nictitans.

To rotate the eyeball:
Obliquus superior,
Obliquus inferior.

To pull the eyeball upward:
Rectus superior.

To pull the eyeball downward:
Rectus inferior.

To pull the eyeball outward:
Rectus externus.

To pull the eyeball inward:
Rectus internus.

To tense the ear drum:
Tensor tympani.

To relax the ear drum:
Circumconcha.

To depress the humerus:
Pectoralis major.

To raise the humerus:
Pectoralis secundus,
Pectoralis tertius.

SPLANCHNOLOGY

The Digestive Apparatus.—This apparatus, apparatus digestorius,
consists of the organs directly concerned in the reception of food, in
its passage through the body, and in the expulsion of the unabsorbed
‘portion. For convenience, these organs are grouped as follows: the
‘alimentary canal and the accessory organs.

The alimentary canal is a tube which extends from the mouth to
the anus. It has a complete lining of mucous membrane, external
‘to which is an almost continuous muscular coat. The abdominal
-portion of the tube is largely covered with a serous membrane, the
visceral peritoneum. ‘The canal consists of the following consecutive
segments: mouth, pharynx, first portion of the esophagus, crop,
second portion of the ésophagus, proventriculus, gizzard, small
intestine, large intestine, and cloaca.

The accessory organs are beak, tongue, salivary glands, liver, and
-pancreas. :

The Mouth (Fig. 27).—The distinctive character of the mouth
of the fowl consists, in the absence of lips and teeth and instead of
jaw bones of other animals, of..a beak. The edge of the beak is
covered by a horn-like gum. The shape of the beak differs in the
various classes of birds. In the chicken the beak is short, strong,
‘thick, and pointed; in palmipeds it is flattened. The upper mandi-
ble extends out over the lower mandible. The outer portion of the
upper and the lower beaks is covered by a horny sheath. There
is no velum, and the mouth cavity is extended rather continuously
into the pharynx (Fig. 27, No. 4). The posterior cross bar of the
hard palate (Fig. 27, No. 5), which possesses a row of filiform papille
projecting backward, marks the upper boundary line of the mouth;
while the posterior end of the tongue (Fig. 27, No. 6), likewise with
a row of filiform papille, marks its lower. boundary line.

Parts of the Mouth—The mouth of fowls is divided into an upper
and a lower half. The upper half is divided into an anterior and a
posterior part. .

The anterior part extends from the anterior tip of the beak to the
posterior nares. It is further divided into an outer hard part and

135

136 ANATOMY OF THE DOMESTIC FOWL

an inner soft part. The outer part-is covered by epithelium which
may be considered as a continuation from the upper outer portion
of the beak. A portion of this is cornified. The inner part is cov-
ered by a mucous membrane containing mucous glands, nerves, and
blood-vessels.

In the posterior part of the upper half of the mouth, are situated
the posterior nares (Fig. 27, No. 10) which appear as a longitudinal

Fic. 27.—Mouth and pharynx of acock laidopen. 1, Eye. 2, Edge of beak
covered with a horn-like gum. 3, Tongue. 4, Pharynx. 5, Posterior cross bar
of hard palate. 6, Posterior end of tongue. 7, Anterior end of esophagus.
8, Phrenum. 9, Palatal papillaries. 10, Posterior nares.

slit in the center of the hard palate. There is also found in this
part a furrow which contains the opening of the Eustachian tubes,
or tube auditive. There are also two ridges near the same pos-
terior part in which are red and white papilla, which may appear
in rows, and which contain mucous glands.

The lower half of the mouth lies between the lower jaw bones and
the walls of the mouth cavity. The tongue is attached here by

SPLANCHNOLOGY 137

means of the phrenum (Fig. 27, No. 8). This half of the mouth
forms a pocket-like structure which aids in taking up the food.

The mouth cavity is lined with stratified squamous epithelium,
continuous with that of the pharynx and the esophagus. Taste
buds are located in the mucous membrane of the mouth.

Fic. 28.—Various anatomical parts of the fowl.

C. A section through the nasal region of the fowl. 1, Nasal passages showing
the turbinated bones dividing the nasal: passage into the superior, middle and
inferior meati. 2, The infra-orbital sinus. 3, The hard palate.

D. Herbst’s touch corpuscle from the beak of a quail.

E. A vertical section through the ductus cochlearis of a pigeon. 1, A blood-
vessel. 2, The periosteum. 3, The bony structure. 4, The vascular integu-
ment. 5, The scala vestibuli. 6, The inner hyaline cylindrical cells. 7, The
membrana tectoria. 8, The papilla acustica basilaris. 9, The membrana basila-
ris. 10, The scala tympani. 11, The ganglion of the cochlear nerve in the
ramus basilaris. 12, The periosteum (Gadow).

F. A corpuscle of the soft papilla of a duck’s tongue. ;

J. A transverse section through a feather papilla. 1, The pulp. 2, The mal-
pighian layer. 3, Thecorium. 4, The stratum corneum of the papilla. 5, The
malpighian cell group of the main shaft. 6, The horny sheath.

In many water fowls, as geese and ducks, the gum edge of the
mandible has grooves extending crosswise, in which are numerous
terminals of the trigeminus nerve arranged as taste organs (Fig. 29,
G and Fig. 28, Dand F). In many birds of prey and in water birds,
e.g., the goose and the duck, there is found at the base of the beak,
a very thin, nervous or sensitive skin, waxy in appearance, called
the ceroma.

138 ANATOMY OF THE DOMESTIC FOWL

2

Fic. 29.—Various anatomical parts of the fowl.

A. 1, The superior semicircular canal. 2, The vestibular nerve. 3, The
meatus auditorius internus—the entrance of the auditory nerve. 4, The entrance
of the cochlear nerve. 5, Posterior semicircular canal. 6, The ampulla.

B. Side papilla of the tongue. 1 and 2, Papille showing a fibrous central core
supporting blood-vessels and nerves. 3, The basement membrane consisting of
connective tissue.

G. Herbst’s corpuscle of the tongue of a duck, showing the capsule, lamella
and around the nerve zone, numerous round bodies arranged in two rows.

SP LANCHNOLOGY 139

The Hard Palate-—The hard palate, palatum durum, forming the
roof of the mouth has for its boundaries the beak anteriorly, the
mandibular arches laterally, and the pharynx posteriorly. It has
four or five transverse bars, projecting posteriorly from each of
which is a row of filiform papille (Figs. 27 and 29).

Fic. 30.—A section through the wall of the crop of a hen. 1, The outer
muscular layer showing longitudinal fibers. 2, The inner muscular layer showing
the sectioned ends of the bundles of muscle fibers. 3, Stratified'squamous epi-
thelium. 4, The outer.surface or lumen of a fold. 5, The stroma, muscularis
mucosa, and submucosa.

The beak (Fig. 4, No. 1) with little if any aid from the tongue,
is the prehensile organ. ,

The Tongue (Fig. 27, No. 3). Locatton.—The tongue (lingua) of
the fowl is situated in the floor of the mouth between the rami of the

H. From the criste acoustica of the ampulla of the dove. A, A vertical section
with isolated fiber cells. 1 and 2, The nerve fibers. 3, The hair cells.

I. A longitudinal section through a feather papilla showing a young feather.
I, The developing feather. 2, The horny sheath. 3, The epithelium. 4,
Stratum corneum. 5, Stratum malpighi. 6, Corium. 7, Malpighian cell
group of the follicle.

140 ANATOMY OF THE DOMESTIC FOWL

lower mandible, and is slung to the cranium by the cerato-branchial
element of the os hyoideum (Fig. 18, No. 2).

Shape.—The tongue, is pointed in front and wide behind, shaped
like an Indian arrow-head, and is supported by the bony and
cartilaginous hyoid apparatus (Fig. 9, A).

Fic. 31.—The visceral organs ofthehen. 1, Tongue. 2, Larynx. 3, Glottis.
4, First portion of the esophagus. 5, Crop. 6, Second portion of the esophagus.
7, Proventriculus. 8, Duodenum. 9, Free or floating portion of the small intes-
tine. 10, Mesentery supporting the free portion of the small intestine. 11,
Ceca. 12, Rectum or large intestine. 13, Cloaca. 14, Anus. 15, Liver.
16, Gall-bladder. 17, Pancreas. 18, Gizzard. 19, Trachea. 20, Lungs.

21, Spleen.

Structure.—The free part of the tongue consists of two long tubes
which are formed by the rolling in of the ventral sides of its horny
coverings. The dorsal plate, which constitutes one-half of the

SPLANCHNOLOGY I41

horny. sheath, does not form a part of the tubes, but ends in the
region of the point of the entoglossum.

The top surface is covered by a thick stratum corneum, giving it
a rather horny surface. Glands occur in the posterior part of the
tongue.

While not so freely movable as in mammals, the tongues of birds
are very flexible.

The Pharynx (Fig. 27). Location:—The anterior part of the
pharynx joins with the mouth and the posterior part with the upper
portion of the esophagus and the superior larynx. The pharynx is
bounded anteriorly by the base of the tongue and by the posterior
edge of the hard palate. Posteriorly, it is marked by the entrance of
the esophagus and by a ridge of filiform papille located on the
supero-posterior part of the larynx, called the palatal papillaries.
A few filiform papille stud the roof. The pharynx communicates
anteriorly with the posterior nares and the mouth, and, posteriorly,
with the esophagus and the larynx.

Shape.—The pharynx is a musculo-membranous sac.

Structure—The pharynx is lined with a mucous membrane
covered by squamous epithelium. The mucous membrane is thrown
into irregular folds. The bird has two Eustachian tubes. Pneu-
matic apertures conduct the air from the Eustachian tubes to the
pericranial diploé.

In the posterior pharyngeal roof is situated the infundibular
crevice.

Function.—The function of the pharynx is to give passage for the —
air from the posterior nares to the larynx, and to give passage for
the food from the mouth to the esophagus. i

Glands Adjacent to the Mouth and to the Pharynx.—The
mucous membrane adjacent to the glottis and in the roof of
the mouth contains alveolar glands. The angular _gland of the
mouth, located beneath the zygomatic arch, by somé anatomists is
considered the rudimentary parotid gland. The sublingual glands,
or glandule sublinguales, are well developed (Fig. 17, No. B, 4).
They form conical masses, with the apex directed anteriorly, and
occupy a portion of the intermaxillary space. Several ducts from
these glands open into the mouth cavity. In the palatine region
there are also located glands called the palatine glands, which open
by many stomata upon the surface.

142 ANATOMY OF THE DOMESTIC FOWL

The Esophagus (Fig. 18, No. 6). Location and Shape.—The
esophagus is a musculo-membranous tube, capable of great dis-
tension, which extends from the pharynx to the proventriculus
(Fig. 35, No. 1, and 3).

The esophagus communicates anteriorly with the pharynx. It
extends down the neck, lying supero-laterally with regard to the
trachea and toward the right-side. It-enters the thorax above the
trachea, and, passing through between the bronchi, terminates into
the proventriculus. At the entrance of the thorax and just to the
right of the median line, it expands into the crop which divides it
into two portions, designated as the first and the second. The
first portion of the esophagus is the longer, the length depending
upon the size and kind of fowl.

Structure-—The wall is composed of four coats, the mucous
membrane, the submucosa, the muscular coats, and the fibrous
sheath or tunic. The mucous membrane is pale and is covered with
stratified squamous epithelium.

The mucous membrane is loosely attached to the muscular coat
by the submucosa. Except during deglutition it lies in longitudinal
folds which. obliterate the lumen. Opening from the mucosa are
lenticular glands, which may be seen on inflating an esophagus
and looking through its transparent walls.

The muscular coat of the esophagus is divided into two layers,
an outer longitudinal and an inner circular layer.

The outer fibrous sheath connects the esophagus loosely to the
surrounding structures.

Function —The function of the esophagus is to give passage way
for the food from the pharynx to the crop and from the crop to the
proventriculus.

The Crop (Fig. 35, No. 2; Figs. 30 and 31). Location and Shape.—
The crop, or ingluvies, saccular in shape, is located at the entrance
of the thorax and just to the right of the median line. The first
portion of the esophagus empties into the crop superiorly and
inferiorly the crop opens into the second portion of the esophagus.
Like the esophagus the crop is capable of great distension.

Structure-—The wall of the crop is composed of four coats, the
mucous membrane, submucosa, muscular and the outer fibrous:

- Thecropis lined with mucous membrane containing mucous glands
, which secrete a mucus to keep the surface moist. The surface of the
mucous membrane is covered by stratified squamous epithelium.

SPLANCHNOLOGY : 143

The submucosa connects the mucous membrane to the muscular
coat.

The wall of the crop is provided with strong muscles. The
fibrous coat, or tunic, connects it with the surrounding structures,

Function.—The crop is a storehouse for the food during the hours
of feeding, the food when needed by the stomach being gradually
discharged from the crop by the contraction of its muscular walls.
The subcutaneous cervical muscles which cover this reservoir aid in
this discharge. ;

In the act of deglutition, the food, after being subjected to the
fluid supplied in the mouth by the adjacent glands, is poised upon
the tongue and swallowed partly by a sudden jerk of the head, and
partly by means of the pressure of the tongue against the hard
palate, the food then passes down the esophagus and: lodges first
in the crop, till needed by the stomach, when it is passed ‘through the
second portion of the esophagus to the first portion of the stomach,
the proventriculus. The time during which food remains in the
crop depends upon the nature of the food. Animal food will, in ty
part, be retained about eight hours and vegetable foods may not one
be passed on for from sixteen to eighteen hours.

The Stomach (Fig. 31, No. 7; Fig. 32, B).—The stomach, or
ventriculus, of fowls is made up of two portions, namely, the pars
glandularis, or proventriculus, and the pars muscularis, or gizzard.

The Proventriculus. Location—The proventriculus lies in the
superior part of the groove formed by the two lobes of the liver, is
inferior to the aorta, and is directed slightly to the left, communicat-
ing anteriorly with the second portion of the esophagus and poste-
riorly emptying into the pars muscularis, the gizzard.

Shape.—The proventriculus is round transversely and elongated,
in fact, nearly fusiform. In the hen of average size it measures about
1.62 inches long and 0.8 inch in diameter.

Structure-—The wall of the proventriculus has four coats, the
mucous, submucous, muscular, and serous.

The inner mucous coat which is raised in folds, is lined with
columnar epithelial cells. The mucous membrane contains lymph-
oid tissue. The mucous coat throughout contains simple tubular’
glands which secrete a highly acid fluid which finds its way to the
surface through small cylindrical ducts lying at right angles to the
inner surface of the mucous membrane (Fig. 32, No.- B, 1).

144 ANATOMY OF THE DOMESTIC FOWL

Fic. 32.—Gizzard and stomach of the fowl.

A. t, Alveolar glands. 2, Mucous membrane of the inner surface of the pro-
ventriculus showing the tubular glands. 3, Connective tissue between the
alveolar glands. 4, An artery. 5, Muscularis mucosa.

B. Photograph of the proventriculus and gizzard. 1, Proventriculus showing
stomata of glands. z, End of duodenum. 3, Gizzard showing hornified epithe-
lium formed into grooves. 4, The heavy muscular walls.

SPLANCHNOLOGY 145

The submucosa, connécts the mucous and muscular coats and
the muscularis layer throws the mucous membrane into folds.

Outside the muscularis mucosa there is another layer (Fig. 32,
A), of simple tubular glands, grouped in lobules, and lined by
cuboidal cells and separated from each other by clefts. These
tubular glands converge toward the center and open into the same
cavity.

The middle muscular coat can be divided into three layers:

two thin, longitudinal layers, arid a thick, circular layer interposed
between the other.two. :
’ Function—The function of the proventriculus appears to be
to soak the food with a secretion. The secretion from the. proven-
triculus is similar to that produced by the fundus glands of the
stomach of mammals. It contains acid and a ferment-pepsin.

The Gizzard (Fig. 31, No. 18). Location—The gizzard, or mus-
cular stomach, occupies a portion of the central part of-the abdominal
cavity (Fig. 33, No. 4). It lies slightly to the left and just behind
the liver, the proventriculus, and the spleen, and rests upon a mass
of intestines. The gizzard communicates at its anterior portion
with the proventriculus and with the duodenum. These openings
are close together. The gizzards of a large number of hens of
average size- averaged in weight as follows: full, 0.215 pound;
empty,_0.126 pound. The gizzard stands perpendicularly and
somewhat obliquely in the abdominal cavity.

Shape.—In shape the gizzard is roundish, flattened laterally.

Structure-—The walls of the gizzard are very thick and are made
up of three coats: mucous, muscular, and serous.

The cavity of the gizzard is covered by a thick skin-like structure
possessing a heavy stratified squamous epithelial layer which is
thrown somewhat into ridges (Fig. 32, B). This membrane becomes
thinnest near the edges.

The mucous membrane, being cornified and readily detachable,
is by some anatomists considered as a special membrane (Fig.
37, B).

At the pyloric opening there is a valve formed by a fold of the’
mucous membrane, which prevents grit and large particles of food
from passing out of the gizzard.

On each side it has a powerful fleshy muscle, the muscularis
lateralis. These musculares laterales are hemispherical, consist of

very closely packed fibers extending transversely, and are attached
10

146 ANATOMY OF THE DOMESTIC FOWL

to strong anterior and posterior ligamentous tendons. They are
joined at the edge of the organ by a strong aponeurosis. The

:

me. be 0

Fic. 33.—View of viscera of the left side of a hen. 1. The base of the heart.
2, Proventriculus. 3, Left lobe of the liver. 4, Gizzard. 5, End of the duo-
denal loop. 6, Pancreas. 7, Free portion of the small intestine. 8, Lungs.

9, Diaphragm.

Fic. 34.—View of the viscera of the right side of ahen. 1, Base of the heart.

3, Right lobe of the liver. 4, Duodenal loop. 5, Pancreas. 6,
7, Large intestine or rectum. 8, Free portion of the floating small
intestine. 9, Gall-bladder. 10, Right kidney. 11, The ribs. Note the lungs

pushing up between them.

2, Lungs.
Cecum.

muscular fibers are red but do not possess cross striations; they are
of the smooth type. The muscularis intermedii, thinner and less

SPLANCHNOLOGY 147

developed than the musculares laterales, occurs on each of the
anterior and the posterior parts of the gizzard.

The serous coat covers over the greater part of the external sur-
face of the gizzard and closely adheres to the muscular coat.

Function.—The hard callous pads of the gizzard, operated by the~
powerful muscles above described, together with grit, act like mill
stones and make reduction to fineness very complete.

At the posterior part there is a sacculated portion containing
glands of the long tubular type which secrete a fluid ferment

Fic. 35.—A median antero-posterior section through the body of a 1-pound
pullet. 1, First portion of the esophagus. 2, Crop. 3, Second portion of the
intestine. 4, Proventriculus. 5, Gizzard. 6, Spleen. 7, Liver. 8, Heart.
9, Point where duodenum was severed from gizzard. 10, Point where duodenum
was severed. 11, Duodenum. 12, Pancreas. 13, Caecum. 14, Floating small
intestine. 15, Ovary. 16, Oil sac.

similar to that secreted by the glands of the pyloric portion of the
stomach of mammals. ‘These glands also exist in a small band near
the entrance of the gizzard. Here the food is mixed with strongly
acid secretion containing pepsin which makes gastric digestion
perfect. a

The Small Intestine (Fig. 31, No. 8 and 9).—The small intestine,
intestinum tenue, is the tube which connects the gizzard with the
large intestine. It is divided into two parts, the duodenum-and the
free portion. Of the three parts as considered in the mammalian

148 ANATOMY OF THE DOMESTIC FOWL

intestine, only the first, the duodenum, can be distinguished. There
is no demarcation between the jejunum and the ileum. The je-
junum and the ileum or that part which represents these sections,
are in coils suspended from the free border of the mesentery the
other border of which is, in turn, attached to the dorsal wall (Fig.
64). The length of the small intestine in a hen of average size is
about 61.7 inches.

Sa),

Fic. 36.

A. Section of the duodenum of the fowl. 1, Villus. 2, Gland. 3, Mass of
lymphoid tissue. 4, Muscularis mucosa. 5, Longitudinal layer. 6, Circular
muscular layer. 7, Serous layer. ;

B. Asection from A ata. 1, The striated free border of the cells. 2, Goblet
cell. 3, Columnar cell. 4, Nucleus of cell. 2

The wall of the small intestine is provided with four coats, as
follows: a mucous, submucous, muscular coat made up of two layers
—the outer, longitudinal and the inner circular layer, and an
external serous.

The mucous membrane which lines the intestine is thick, soft, and
highly vascular. It has a velvety appearance, due to numerous long,
thin projecting villi. The villi (Fig. 36, A) are concerned in the
absorption of the digested food, absorbing principally the emulsified

s. Each villus is covered with a single layer of high columnar ‘
epithelial cells. Some of these, the so-called goblet cells, provide

SPLANCHNOLOGY 149

mucin which lubricates the mucous surface. These cells are found
in all mucous surfaces and prevent the surface from becoming dry.
There are a few goblet cells near the summits of the villi. Open-

Fic. 37.—Histological studies of various anatomical parts.

A. A transverse section of the first portion of the esophagus of a fowl. 1,
The outer longitudinal muscular layer. 2, The circular muscular layer. 3, The
submucosa. 4, The muscularis mucosa. 5, Stroma. 6, Epithelial layer. 7,
The lenticular glands. 8, The lumen. :

B. A transverse section of the proventriculus. 1, The outer longitudinal
muscular layer. 2, The middle muscular layer. 3, The inner longitudinal mus-
cular layer. 4, Stroma. 5, The muscularis mucosa. 6, The submucosa. 7,
Stroma. 8, Tubular glands. 9, Tubulo-alveolar glands. 10, A tubulo-alveolar
gland with the tubular glands cut transversely. 11, The lumen of the proven-
triculus.

C. A section of the inner wall of the gizzard. 1, The hyaline mucous mem-
brane. 2, Branched tubular glands. 3, Submucosa. 4, Muscle. 5, A con-
nective tissue septum. :

D. A transverse section of the small intestines. 1, The outer longitudinal
muscular layer. 2, The inner circular muscular layer. 3, The muscularis
mucosa. 4, The stroma. 5, Brunner’s glands. 6, A villus. 7, Mass of lym-
phoid tissue.

E. A transverse section through the cecum. 1, The outer longitudinal mus-
cular layer. 2, The inner circular muscular layer. 3, The submucosa. 4, The
muscularis mucosa. 5, The stroma. 6, Tubular glands. 7, The lumen.

F. The cerebellum showing the arbo-vite. 1, White, fiber portion. z, The
granular layer. 3, The layer of Purkinje cells. 4, The molecular layer.

ings of simple intestinal tubular glands the duodenal glands, or the
glands formerly known as Brunner’s glands, are located between the
villi. These glands secrete the succus entericus, or intestinal juice?
These openings, or stomata, are lined with granular cells The -

I50 ANATOMY OF THE DOMESTIC FOWL

reaction of the contents of the small intestine is strongly acid, but:
gradually less so in proportion to the distance down the intestinal
tract until the czca are reached, where the reaction is found to be
faintly acid, neutral, or slightly alkaline. a

Function.—The function of the small intestine is that of digestion
and absorption. :

The Duodenum. Location and Shape-—The duodenum, a small
tube, originates from the gizzard about 14 inch to the right of
the entrance of the proventriculus. Extending from left to right,
it passes under and behind the gizzard along the inner side of the
right abdominal wall backward to the posterior portion of the wall,
and a trifle more than half way toward the left side, where-the loop
rests. This loop, the duodenal loop, is about 5 inches in length (Fig.
31, No. 8). The two branches of the loop the first and the second
portions or the descending and ascending limbs, are loosely held by
connective tissue, and have the pancreas lodged between them.

The Free Portion of the Small Intestine. Location.—That sec-
tion of the small intestine following the duodenum is called the free
portion of the small intestine and occupies the space between the
abdominal air-sac and the median line of the abdominal cavity.
It is disposed in coils and is suspended from the dorsal wall of the
abdomen by a thin membrane, the mesentery.

The bile ducts enter the small intestine about 14 inches from
its point of origin. The pancreas also pours its contents into the |
small intestine. :

The Large Intestine (Fig. 31, No. 12). Location—The large
intestine extends in a straight line along the inferior border of the
vertebral column communicating anteriorly with the small intestine,
and the caca and posteriorly with the cloaca.

Shape-—The diameter of the large intestine is approximately
twice that of the small intestine. In fowls of average size its mean
length is 4.61 inches. The large intestine hassometimes been spoken
of as the rectum, or straight gut.

Structure.—Like the small intestine the large intestine has four
coats: an inner mucous, a submucous, a middle muscular and an
outer serous. The folds of mucous membrane of the large intestine
have tubular glands lined with columnar cells (Fig. 37, A No. 1).

Function.—The large intestine is similar in function to that of ther
small intestine, in that digestion and absorption may take place
within it.

SPLANCHNOLOGY 151i

The Czca (Fig. 31, No. 11). Location —The fowl has two ceca
extending forward from their point of origin at the juncture of the
small and large intestine.

Shape.—The ceca average 7.61 inches in length.. They are large
in caliber toward the blind extremity and are constricted near their
origin..

Structure-—The parietal coats are continued from the small
intestine.

Ebarth has described an elevated body in the cecum, which is
located about 4 millimeters from the opening and is composed en-
tirely ‘of lymphoid tissue.

A tea

Fic. 37A.—Photomicrograph of a transverse section of large intestine and
oviduct just anterior to the cloaca, showing the tubular glands of the large intes-
tines, mucosa of oviduct with intervening structures. 1, The tubular glands of
large intestine, or rectum. 2, Muscular wall of intestine. 3, Wall of the ovi-
duct. 4, Mucosa of the oviduct.

The ceca are usually partly filled with a soft pultaceous material
of a pasty consistency.

The Cloaca (Fig. 31, No. 13). Location.—The rectum opens by a
circular, valvular orifice into the dilated portion just in front of the
anus, which dilatation is called the cloaca.

Shape.—The cloaca is saccular in shape.

Structure—The cloaca is divided into two portions, the copro-
deumal and the urodeumal. That portion of the cloaca into which
the intestine empties is called the coprodeum; and the ureter and

152 ANATOMY OF THE DOMESTIC FOWL

oviduct empty into the urodeum. The seminiferous tubules,
carrying the semen from the testes in the male empty in teat-
like projections on the cloacal mucous membrane into the urodeu-
mal portion. The cloacal walls are similar in structure to the large
intestines.

On the dorsal wall of the cloaca between it and the spine, is a
small sac, called the bursa of Fabricius, which hasa duct communicat-
ing with the cloaca. The mucous membrane of this sac is thrown
into folds and is studded with glands. The bursa of Fabricus is
larger in the young than in the adult bird. It apparently atrophies
as the bird becomes older. When the bird is four months old this
bursa is best developed, and at this age it may be as large as 2 or 3
centimeters in diameter.

Function.—The function of the cloaca is to give passage way to
the feces, the urine, and the egg and to act as an organ of copulation.
- Course of the Food.—The food first enters the mouth, after being
picked up by aid of the beak. From here it passes through the
pharynx and first portion of the esophagus to the crop, without
mastication, as the bird is not provided with teeth. The food is
passed from the crop by aid of its muscular walls as needed; thence
through the second ‘portion of the esophagus to the proventriculus,
an expansion in the digestive tube just before it terminates in the
gizzard. The glands of the proventriculus produce a secretion in
which the food is soaked before passing into the gizzard. The
gizzard is provided with strong muscular walls which, by aid of grit,
thoroughly reduce the food to fineness. From the gizzard the food.
passes through the first portion of the small intestine, where it is
subjected to the action of the bile from the liver, the pancreatic ,
juice from the pancreas, and of the succus entericus from the glands
of the intestinal wall. The food is then passed into the ceca. The
indigestible portion of the food passes from the ceca through the
large intestine, or rectum, to the cloaca and thence to the external
world.

The digestive functions of the bird are very potent and rapid.
This compensates for the waste caused by their extensive, frequent,
and energetic motions, and is in accordance with the rapidity of their
circulation and their high state of irritability. anes
ee eo ee

THE ACCESSORY ORGANS OF DIGESTION

The accessory organs of digestion are the liver, pancreas, and
some anatomists include also the spleen. The first two manufacture

SPLANCHNOLOGY 153

fluids containing ferments which aid in splitting or digesting the
food:

~The Liver (Figs. 31, 33 and 34). Locatton.—The liver, hepar,
lies ventrally and posteriorly to the heart. It is related anteriorly
with the diaphragm, inferiorly with the sternum, posteriorly with
the gizzard and intestine, and superiorly with the ovary, oviduct
and proventriculus and laterally with the abdominal wall.

Shape.—The liver is a voluminous deep livid brown gland, soft
and friable in texture. It is divided into two principal lobes, a
right and a left.

The right lobe is larger than the left. In the hen of average size
the liver weighs 35 grams. The parietal surface is convex and
smooth. The surface which lies against the viscera is irregularly
concave. The visceral surface furnishes exit for the bile duct and
passage for the nerves and blood-vessels. This part is called the
porta. :

The left lobe may be cleft from below so deeply as to form two
lobes on that side.

Structure-—Each lobe is covered by a double serous membrane,
one closely adherent, the other surrounding the structure loosely.
These tunics, which are reflections of the peritoneum, are continued
from the base of the liver, over both the anterior, and the posterior
surface. The loose layer is formed by the air cells surrounding the
lobes. The thin border of the liver is usually free.

The two-lobes of the liver are connected by a narrow isthmus of
liver tissue. Occasionally there is a bird in which there occurs a
lobus Spigelii located at the posterior of the liver between the two
principal lobes.

The apex of the heart sacculates the diaphragm backward, so that
part of this apex lies between the right and the left lobes (Fig.
43, No. 6 and 7). A ligament, the falciform, extends from the apex
of the pericardial membrane, and attaching it rather firmly to the
central connective tissue, or interlobar ligament. This ligament
also has attachments to the inner surface of the sternum. The
broad ligament of the liver is formed posteriorly by a fold of the
peritoneum.

The interlobar, or principal, ligament of the liver is formed .by a
large and strong duplicature of the peritoneum, which makes a
longitudinal division in the abdominal cavity similar to the lateral
division made by the thoracic mediastinum in mammals. It

I 54 ANATOMY OF THE DOMESTIC FOWL

is reflected upon the pericardium from the linea alba and the middle
line of the sternum, and passes deeply into the interspace of the
lobes of the liver. It is attached to these lobes throughout their
whole length and connects them below to one side of the gizzard.
The lateral and posterior part of the liver attach to the adjacent air
cells, and the whole viscus is thus kept fixed in its position during
rapid and violent movements of the bird.

The remains of the umbilical veins are traceable within the dupli-
cature of the membranes forming the septum. These remains thus
represent the round ligament of mammals.

Fic. 38.— Cellular structure of liver, pancreas, and trachea.

A. Liver. 1, Liver cells. 2, Sinusoid. 4, Nucleus of cells.

B. Pancreas. 1, Island of Langerhans. 2, Alveolar cells. 3, Duct.

C. Trachea. 1, Ciliated epithelia. 2, Glands. 3, Hyaline cartilage.

D. Section of wall of ovum at Fig. 57 letter d. 1, Yolk. 2, Granular mem-
brane. 3, Theca. 4, Blood-vessel.

A microscopic study of the liver of the fowl shows a compact mass
of liver cells polyhedral in shape, with large nuclei (Fig. 38, A).
The liver tissue differs from that of mammals in that there is no
clearly outlined lobular arrangement; neither is the outline of the
individual cell so well marked. The parenchymatous portion is
made up of columns of liver tissue. These columns anastomose and
show narrow channels between. They are best seen in the young
chick. :

Function.—One of the functions of the liver is to secrete bile. A
gall-bladder, which receives part of the bile secreted by the right lobe
of the liver, is located on the posterior face of this lobe. Extending

SPLANCHNOLOGY 155

from this gall-bladder there is a duct, the cystic duct, which empties
into the small intestine toward the extremity of the second branch of
the duodenal loop. Another duct called the hepatic duct, proceeds
directly from the two lobes of the liver and empties into the intestine
just in front of the cystic duct.

The Pancreas (Fig. 31, No. 17). Location and Shape.—The pan-
creas, an organ lying in the duodenal loop is a yellowish-white, lobu-
lated gland, elongated in shape. Its average length in fowls of
average size is 4.96 inches, and the average weight about 0.008 pound.
The pancreas is divided into lobes, which in turn are divided into
lobules.

Structure-—The pancreas has a supporting connective tissue.
The lobules are made up of small alveolar glands, which are lined '
with columnar epithelial cells. The ducts leading from the alveoli
are small; these unite to form larger ducts in which the epithelium
is taller. Between the alveoli throughout the pancreas there are
clusters of polyhedral cells which form the islands of Langerhans.
These islands are said to produce an internal secretion, or hormone,
which is absorbed by the blood or lymph capillaries and thus enters ©
the circulation (Fig. 38, B). ;

Function.—The function of the pancreas is to secrete a fluid con-

Maining digestive ferments.

The Spleen (Fig. 31, No. 21). Location ——The spleen, or lien,
lies in a triangle formed by the proventriculus, the liver, and the
gizzard.

Shape.—It is a reddish-brown body shaped like a buckeye, is small
in size, weighing only about 0.005 pound.

Structure-—The outer surface of the spleen is covered by a reflec-
tion of the peritoneum. After this covering is removed, there is
observed a firm, white, fibrous layer, the cortical portion. This
covering sends into the interior small and large trabecule, forming
a framework and dividing it-into acini, or compartments. The
spaces are filled with a dark red parenchymatous material called
splenic pulp. The framework, in both deep and surface portions,
are found elastic fibers and smooth muscular fibers.

The spleen is essentially a lymphatic organ, its peculiar structure
deooting Inge tear the eee of the blood-vessels.
Compact lymphatic tissue occurs in the spleen in spherical, oval, or
cylindrical collections of closely packed lymphoid cells. These
masses are known as the Malpighian bodies, or splenic corpuscles.

156 ANATOMY OF THE DOMESTIC FOWL

They are distributed throughout the splenic pulp. Each splenic
corpuscle contains one or more small arteries. These extend near
the periphery of the corpuscle and more rarely in the center.

The splenic artery passes in and the splenic veins out at the
hilum which is located on the concave, or attached, side of the
spleen. The splenic artery, upon entering the organ, at once
branches, the trabecula forming a support for the vessels.

After the arteries have entered the hilum, as stated above, they
divide into many branches which follow the septa of the connective
tissue. At first the arteries are accompanied by branches of the
splenic veins. Soon, however, the arteries leave the veins and the
septa, and penetrate the splenic pulp. In the splenic pulp the
adventitia of the smaller arteries assume the character of reticular
tissue, and become infiltrated with lymphoid cells. This infiltration
forms masses which are called the splenic corpuscles, or Malpighian
bodies. The terminal arteries break up into capillaries, which still
retain an adventitia, and empty into border spaces, or sinuses,
sometimes spoken of as ampulla. These sinuses in turn empty into
cavernous sinuses of the splenic pulp. From these are finally
formed the venules; and the collections of venules form the splenic
veins through which the blood gains exit from the spleen.

The Abdominal and Pelvic Cavities.—In birds the abdominal
cavity is divided into two smaller cavities by a fibrous septum. The
anterior cavity representing the abdominal contains the liver, and
the other representing the pelvic contains the gizzard, intestines and
oviduct.

va The Peritoneum and the Mesentery.—The abdominal and pelvic
Cavities are lined by the peritoneum. Like all serous membranes
this is composed of a parietal and a visceral portion, which together
form a complete sac, with the organs it covers situated on the outer
side. The peritoneum like other serous membranes consists of a
mesothelial and a submesothelial portion, the cells of the former
being arranged in a single layer. Since a serous membrane is so
arranged as to line a closed cavity, and at the same time to cover
its contents, it follows that the entire membrane must be a closed
sac, the mesothelial layer being on the inside; such a sac is called
a serous sac, or cavity. Synovial membranes are also regarded as
a variety of serous membranes. The fold, or layer, of the mem-
brane which lines the cavity is called the parietal, that which
covers the greater part of the organs contained therein is called the

SPLANCHNOLOGY 157

visceral portion; the two surfaces contacting, and gliding upon each
other, are lubricated by a fluid secretion contained in the sac; hence
one use of these membranes is to prevent friction between the walls
of cavities and the organs contained therein. . Serous membranes
line the abdominal cavity, pericardium, cavities of the heart and is
continuous throughout the vascular structures.

Fic. 39.—A transverse section of body of hen through 15, Fig. 34. R, Right
side. L, Left side. 1, Spinal cord. 2, Esophagus. 3, Trachea. 4, Skin. 5,
Pectoral muscles.

The serous membrane besides covering the external surface of the
viscera, double folds pass from one organ to another, or from an
organ to the parietes of the cavity. These double folds of the
peritoneum are known as ligaments, or as mesenteries. In ligaments
the two folds are strengthened by an interposed layer of fibro-elastic
tissue. A mesentery is a broad, double fold of peritoneum, attached
to the abdominal parietes above, and containing a portion of the
intestine in its free or remote extremity. Between its folds we find
blood-vessels, nerves, and lymphatics or lacteals, hence it permits

158 ANATOMY OF THE DOMESTIC FOWL

vascular and nervous communications with the organ attached to it.
The free portion of the small intestine is attached to the free margin
of the mesentery.

THE RELATIONS OF THE VISCERAL ORGANS OF THE
DOMESTIC FOWL

Figure 33 shows a fowl with the left abdominal wall and the left
thoracic wall removed. No. 1 in this figure shows the base of the

Fic. 40.—Transverse section through the body of a hen through 14, Fig. 34.
R, Right side. L, Left side. 1, Spinal cord. 2, Esophagus. 3, Trachea near
inferior larynx. 4, Lungs. 5, Pectoral muscles.

heart in front of the left lobe of the liver. Above the liver is the
proventriculus; above this, the diaphragm; and above the diaphragm
--and the base of the heart the left lung occupying the superior part
of the thoracic cavity, and that there is no distinct pleural sac, as
in mammals but that the lung pushes out between the ribs, thus
pressing against the ribs on the inner and the lateral sides. The
gizzard is back of the liver, to the left side of the abdominal cavity,

‘SPLANCHNOLOGY 159

and beneath and in front of the duodenal loop. The small intestine
from this side is above the gizzard. Supero-anterior to the gizzard
is the blind end of the cecum. The pancreas is within the duodenal
loop.

Figure 34 shows the viscera from the right side after the re-
moval of the right abdominal and the right thoracic wall. The
base of the heart is in front of the right lobe of the liver. Above

Fic. 41.—Transverse section through the body of a hen at 12, Fig. 33. R,
Right side. L, Left side. 1, Spinal cord. 2, Esophagus. 3, Inferior larynx.
4, Base of the heart. 5, Aorta. 6, Vena cava. 7, Lungs. 8, Skin. 9, Pec-
toral muscles.

these the right lung occupies the upper part of the thoracic cavity as
in the preceding illustration. Just back of this is the anterior lobe
of the kidney. The gall-bladder is observed at No. 9 on the right
lobe of the liver. Just inferior to a longitudinal central line is the
duodenal loop, between the limbs of which is seen the pancreas.
Above this loop the caca are located. The gizzard is not visible

160 ANATOMY OF THE DOMESTIC FOWL

from the right side; on this side posterior to the liver is the small
intestine. Superior to this at No. 7 the rectum.

The relative position of the visceral organs in the median line is
observed in Fig. 35. No.1 of this figure shows the stump of the
first portion of the esophagus, and No. 2, the left wall of the crop.
Following this, and located just below the vertebre is the second

Fic. 42.—Transverse section through the body of a hen at 11, Fig. 33. R,
Right side. L, Left side. 1, Spinal cord. 2, Vertebra. 3, Spinous process
of vertebra. 4,Lungs. 5, Esophagus. 6, Pericardialsac. 7, Sectioned surface
of heart. 8, Auricle of heart. 9, Blood clot in right auricle. 10, Section of
sternum. 11, Pectoral muscles.

portion of the esophagus. The major portion of the crop is located
on the right side.

It will be noted that the second portion of. the esophagus passes
over the base of the heart and the superior part of the liver, and then
terminates in the proventriculus. The proventriculus extends down-
ward and empties into the gizzard. This organ lies antero-laterally
to the gizzard, supero-posterior to the liver, and to the left of the
spleen. The spleen lies in a triangle formed by the liver, the pro-

SPLANCHNOLOGY 161

ventriculus, and the gizzard. The heart is noted to lie supero-an-
terior to the liver, and between the anterior portion of the fissure
formed by the right and the left lobe. The ovary is located back of
the diaphragm at the anterior end of the kidney and below the in-
ferior surface of the bodies of the vertebra. The bulk of the floating
portion of the small intestine is located above the gizzard.

Fic. 43,—Transverse section through the body of a hen at 13, Fig. 34. R,
Right side. L, Left side. 1, Spinal cord. 3, Body of vertebra. 3, Superior
spinous process of vertebra. 4, Lungs. 5, Esophagus. 6, Heart. 7, Right
and left lobes of liver. 8, Sternum. 9, Skin. 10, Pectoral muscles.

A transverse anterior section of a normal laying hen is shown
in Fig. 39, the section being made at 15 of Fig. 34. At this
point the esophagus lies centrally and above the trachea. Figure
4o shows a transverse anterior section through the thoracic region
at 14 of Fig. 34. At this point the esophagus is slightly to the
right of and is superior to the trachea. At this level the apex of
the lung is sectioned. This is in the region of the cervical air-sac.
Figure 41 shows a posterior section at 12 of Fig. 33. The

11

162 ANATOMY OF THE DOMESTIC FOWL

esophagus here-is above and to the right of the inferior larynx, and
directly below and between the lungs. The inferior larynx is
above the base of the heart.

Figure 42 shows a transverse anterior section made at 11 of Fig.
33. It shows that at this level the esophagus is centrally lo-
cated and passes over the base of the heart. The heart occupies

Fic. 44.—Transverse section through the body of a hen at 12, Fig. 34. R,
Right side. L, Left side. 1, Spinal cord. 2, Articular surface of vertebral seg-
ment. 3, Endofrib. 4, Lungs. 5, Proventriculus. 6, Liver showing Glisson's
capsule. 7, Sternum. 8, Pectoral muscles. 9, Skin.

the lower portion of the thorax and the lungs the upper. Figure
43 shows a photograph of a transverse anterior section of the body
made. at 13 of Fig. 34. At this level the apex of the heart lies
within the anterior fissure of the liver. The sectioned portion of
the heart shows the lower portion of the ventricle.

In this figure the lungs show, on the sectioned surface, the ends of

SPLANCHNOLOGY 163

‘
some of the larger bronchi. The esophagus is located above the
heart. Showing the relations of the visceral organs back of the
heart girdle, photograph number 44, gives an anterior section made
at 12, Fig. 33. The lungs are spread out occupying the posterior
thoracic region and below at No. to is the diaphragm. The dia-
phragm does not appear to have that rigidity and firmness of position

Fic. 43.—Transverse section through the body of a hen at 10, Fig. 33. R,
Right side. L, Left side. 1, Spinal cord. 2, Body of vertebra. 3, Lungs,
4, Ova. 5, Proventriculus. 6, Liver. 7, Sternum. 8, Skin. 9, Pectoral
muscles.

asin mammals. Itisrather rudimentary. Below the left lung and
above the left lobe of the liver is the proventriculus. Note that
the viscus is empty and that the mucous membrane is thrown into
folds. At this point the liver occupies much of the abdominal
cavity. Figure 45 is a view of an anterior section made at 10,

164 ANATOMY OF THE DOMESTIC FOWL

Fig. -33. In this section the lungs are decreasing in caliber.
The liver occupies much of the space in the lower right abdominal
quadrant, and above and to the right is the ovary with many of the
ova developing yolks. Below No. 4 which is a developing yolk, is
the proventriculus. Figure 46 is a view of an anterior section

Fic. 46-—A transverse section through the body of a hen at 9, Fig. 33. R,
Right side. L,Left side. 1, Spinalcord. 2, Vertebra. 3, Kidneys. 4, Ovary.
5,Cacum. 6,Smallintestine. 7,Gizzard. 8, Right lobe ofliver. 9,Skin. 10,
Pectoral muscles.

made at 9, Fig. 33. At this level are shown sectioned surfaces
of the kidneys, which lie on either side of the spinal column. Below
the spinal column and occupying the left upper quadrant is the
ovary containing ova in the process of developing yolks. To the
right is the sectioned surface of one of the ceca and below this and
on the right side is the sectioned ends of many of‘the loops of the

SPLANCHNOLOGY 165

floating portion of the small intestine. Occupying the left lower
quadrant is the sectioned surface of the gizzard and on the abdominal
floor and to the right of the gizzard, the posterior end of the right
lobe of the liver.

THE RELATIONS OF THE VISCERAL ORGANS OF THE BABY CHICK

There is approximately 47 per cent: of the yolk retained in the
abdominal yolk sac of the baby chick at hatching. Figure 47

Fic. 47.—An antero-posterior section through the body of a baby chick just
hatched. 1, Abdominal yolk'sac. 2, Gizzard.. 3, Liver. 4, Heart. 5, In-
testines. 6, Spinal cord. 7, Cerebrum. 8, Cerebellum. 9, Fat in the post-
occipital region. 10, The thymus gland.

shows a photograph of a longitudinal section through a baby chick.
This figure shows all the posterior portion of the abdominal cavity
occupied with abdominal yolk. The abdominal viscera are pushed
forward, and as the yolk is gradually absorbed the visceral organs
gradually occupy their normal position.

A section through this body Fig. 47 at A is shown in Fig.
48, A. At this point the esophagus appears below the vertebral
column. Figure 48, B, a section through the body at Fig. 47, B,
shows the apex of the lungs. In a median line and below the lungs
is the esophagus. Note the mucous membrane thrown into folds.
Here the heart is sectioned, showing both auricles and both ventri-

166 ANATOMY OF THE DOMESTIC FOWL

Fic. is .—Transverse sections of the body of a baby chick at hatching.
Right side. L, Left side.
A.A eases section at A, Fig. 50. I, Spinal cord. 2, Esophagus.
Entrance to thorax. 4, Stubs of the wings.
B. A transverse section at B, Fig. 50. 1, Spinal cord. 2, Esophagus.
Lungs. 4, Heart.
C. A transverse section through the body at C, Fig. 50. 1, Spinal cord.
Lungs. 3, Esophagus. 4, Liver. 5, Heart.

D. A transverse section at D, Fig. 50. 1, Spinal cord. 2, Proventriculus.

3, Liver. 4, Gizzard. 5, Intestine. 6, Kidneys. 7, Gall-bladder.

SPLANCHNOLOGY 167

cles. This is a view looking forward. Figure 48, C, is a view of a
posterior section made at Fig. 47, C. It shows the same relations
of the esophagus and lungs, but shows at this level both the right and

Fic. 49.—Transverse section through the body of a baby chick.
E at E, Fig. 50. 1, Spinal cord. z, Kidneys. 3, Gizzard. 4, Intestines.

5, Unabsorbed yolk. 6, Stubs of legs. ;
F. A section at F, Fig. 50. 1, Spinal cord. 2, Kidneys. 3, Intestine. 4,

Unabsorbed yolk.
G. A section at G, Fig. 50. 1, Anus. 2, Umbilicus.

the left lobe of the liver. Between these lobes we note the sectioned
apex of the heart. Figure 48, D shows a posterior section at Fig

168 ANATOMY OF THE DOMESTIC FOWL

47, D. At this level the kidneys are above and infero-laterally
to the spinal column. The intestines are below the kidneys; and on
the left side, between the kidneys and left lobe of the liver, and
near the abdominal wall, is the proventriculus. Occupying the ma-
jor portion of the inferior abdominal cavity are the right and the
left lobe of the liver, and between these the anterior border of the
gizzard. Note the gizzard sitting at an angle inclining toward
the left side. Figure 49, E shows a section at Fig. 47, E. Here
the gizzard occupies the left lower abdominal quadrant. To the
right are the intestines; and directly above the gizzard is a small
portion of the anterior end of the abdominal yolk sac. Infero-lat-
erally are the kidneys. Figure 49, F, shows the kidneys similarly
located as in the preceding; and just below is the rectum suspended
by the mesentery. The rest of the cavity is occupied by the ab-
dominal yolk.

THE URO-GENITAL SYSTEM

The uro-genital apparatus, or apparatus uro-genitalis, consists
of two groups of organs: the urinary and the genital. The former
elaborate and remove the chief excretory fluid, the urine; and the
latter serve for the formation, development, and expulsion of the
products of the reproductive glands.

THE URINARY APPARATUS (Fig. 50 and Fig. 51).

The urinary apparatus of the bird consists of two kidneys, from

each of which a ureter extends and empties into the cloaca.
_ The Kidneys. Location—The kidneys are located in excavations
in the pelvic roof. They are related internally with the posterior
aorta and vena cava, supero-internally with the lumbo-sacral ver-
tebree and superiorly and supero-externally with the ilium. The
abdominal visceral organs lie below the kidneys. The kidneys are
external to or above the peritoneum.

Shape.—In the fowl of average size the kidneys are 214 inches
long and are made up of three irregular lobes. The anterior lobe
is usually the largest and the middle the smallest. The anterior
border of the first lobe is located opposite the last true dorsal articu-
lation. ‘The anterior lobe is called the anterior pelvic or ilio-lumbar
lobe, the middle the middle pelvic or ilio-sacral lobe, and the posterior
the posterior pelvic lobe.

Structure—The whole kidney has a fine transparent covering.
The dark, brownish-red parenchyme can be seen through this mem-
brane. It has a blood vascular system and a urinary tubular sys-
tem. The larger arteries, the veins, and the nerves pass between the
lobules, and the smaller vessels: between the tubules. These form
fine network or plexuses. The lymphatic vessels are very few, and
are mainly found on the surface. The kidneys are pierced in their
posterior third by the external iliac artery and at about its middle
by the venous branches forming the posterior vena cava.

The lobes are made up of lobules, which are plainly perceptible
from the external surface. Each lobule is apparently a unit within

169

170 ANATOMY OF THE DOMESTIC FOWL

itself. It receives its blood supply from small branches of the
renal artery and is made up of a cortical or peripheral portion which
contains the glomerules (Fig. 52, A) and a medullary portion,
which is made up of tubules, or urinary canals, arteries, veins, and
nerves.

8 and

1, Heart.

3, The anterior, middle and posterior lobes of the
5, Terminal

7, The brachial nerve plexus.

4, The lumbo-sacral segment of the spinal cord.
9, The lumbar nerves.

6, The cervico-dorsal segment of the spinal cord.
8, The ischiadic nerve.

Note the indentations made by the ribs.

The lobules are plainly visible.

Fic. 50.—Photograph showing spinal cord and relative positions of the kidney, lung and heart.

9, The lumbo-sacral plexus.

2, Lung.
kidney.
cord filament.

The urinary canals are divided into two kinds, namely, the outer
and the inner tubular systems. The outer canals, called the tubule
urinifert corticalis, are very small in caliber and are located in the

THE URO-GENITAL SYSTEM 17r

lobules. The renal artery (Fig. 53, No. B,. 3) breaking up into
arterioles in the kidney, and finally reaching the cortical portion
of the lobules, form capillary plexuses in the shape of minute spheres,
which are the glomerules (Fig. 53, No. C, 3 and B, 5). Around each
glomerule there is formed a capsule called Bowman’s capsule, which
is the beginning of the uriniferous tubule. This entire mass is called
the Malpighian body, or renal corpuscle. This capsule then ex-
tends as the urinary, or secreting tubule, being at first constricted,
then convoluted, and terminates into a second portion, the descend-

Fic. 51.—The kidneys. sa, The posterior, 1b, the middle and 1c, the anterior
lobes of the kidney. 2, The posterior aorta. 3, The external iliac or crural
artery. 4, The ischiadic artery. 5, The sacralis media artery. 6, The ureter
which empties into the cloaca at 7. 8, Theexternal iliac vein. 9, The internal
iliac vein. 10, The iliacus communis.

ing limb of Henle. This portion of the tubule becomes constricted.
It then forms the loop of Henle and ascends as the second portion,
or second limb of Henle, which is again of greater diameter. The top
of the secreting tubule is slightly wavy and empties into the col-
lecting tubule along with many others. These collecting tubules
in turn merge into large tubules which finally empty into the ureter
(Fig. 53, No. 14).. These collective bundles correspond to the pyra-
mids of the kidneys of mammals.

172 ANATOMY OF THE DOMESTIC FOWL

The neck of the uriniferous tubule as it emerges from Bowman’s
capsule is short and narrow and is lined with a few cuboidal cells.

Fic. 52.

A. Photomicrograph of a section of a kidney showing three lobules. 1, Cor-
tical portion of lobule showing glomeruli. 2, The central or medullary portion
oi thelobule. 3, The outer surface of the kidney.

B. Salts from the urine of a hen. 1, Uric acid crystals. 2, Sodium urate
crystals. '

Toward the glomerular end the cells are of a transitional form gradu-
ally merging into the flat squamous type peculiar to Bowman’s

THE URO-GENITAL SYSTEM 173

capsule. The first convoluted tubule is lined with irregular cuboidal
or pyramidal epithelial cells. The descending limb of Henle’s loop
is narrow and is lined with a simple layer of flat epithelial cells. In

Fic. 53.—The renal structure.
A. 1, Capillary blood-vessel. 2, Descending limb of Henle. 3, Collecting
. tubule. 4, Ascending limb of Henle.

B. 1, Branch of renal artery. 2, The descending or medullary branch. 3,
The ascending branch. 4, The arteriole taking part in the formation of the
glomerule. 5, Theglomerule. 6, Bowman’scapsule. 7, Blood-vessel extending
from the glomerule. 8, The vein of the medullary part of the lobule. 9, The
neck. 10, The convoluted tubule. 11, The descending limb of Henle. 12,
Henle’s loop. 13, The ascending loop of Henle. 14, The collecting tubule.

C. 1, Section through a convoluted tubule. 2, Bowman’s capsule. 3, The
glomerule. :

the loop the epithelium changes from the flat type in the descending
limb to the cuboidal in the ascending limb. The ascending limb of
Henle’s loop again becomes broader and is lined with low cuboidal
cells. The second convoluted, or tortuous, tubule is lined with low

174 ANATOMY OF THE DOMESTIC FOWL

cuboidal cells as are also the collecting tubules. The collecting
tubules originate from every part of the internal substance of the
lobules, and extending to the gyrations, uniting in the pinniform
structure and traversing to the margin of the lobules, following along
‘the uneven surface, infero-laterally and toward the median body line,
finally empty into the ureter.

‘There are many arterial branches given off from the arteria re-
nalis. The arteries which supply the kidneys are given off from the
posterior aorta and ischiadic artery. As soon as these arteries enter
the kidney they break up into two systems. One system supplies
-. the kidney substance with nourishment in the form of nutrient blood;
the second system supplies the glomerules with what may be con-
sidered functional blood (Gadow). The second system of arteries :
branches, into the small arteria interlobularis, which pass between
the lobules of the kidneys where they give off side branches which
penetrate the cortical portion of the lobules and form the capillary
plexus, the glomerule.

The arteriole that enters into the structure of the glomerule is
lined with endothelial cells and is surrounded by a few muscle fibers
and a fine network of connective tissue. The vessel that carries the
blood away is similarly constructed.

Function—In the glomerules the liquid portion of the urine is
filtered out of the blood, which urine flows through the uriniferous
tubules and passes from the kidney through the ureter. In the
cubical cells are extracted the solid portions of the urine which also
pass through the tubules with the liquid. The urinary secretion,
as found in the ureter, does not contain much liquid, but, on the con-
trary, is made up of a pasty material consisting of salts which are,
for the most part, uric acid crystals and sodium urate (Fig. 52, B).
This material becomes hard, like cement, soon after being exposed
to the atmosphere. This secretion may be noted as a whitish pasty
material on the outer parts of the feces, or droppings, voided by the
birds.

The Ureter. Location.—The ureter extends along the inferior sur-
face of the kidney. It has its origin near the anterior extremity of
the kidney, and passing posteriorly the entire length of the kidney
receives tributary collecting tubules, and terminates in the upper
wall of the cloaca in the urodeumal portion.

Shape.—The ureter gradually enlarges in diameter until it reaches

THE URO-GENITAL SYSTEM 175

the posterior border of the kidney, and then maintains about the
same caliber throughout the rest of its course.

Structure.—The ureter wall is made up of three coats as follows:
mucous, muscular and fibrous.

Function.—The ureters serve as a passage way for the urine from
the kidneys to the cloaca.

THE MALE GENERATIVE ORGANS (Fig. 54)

The male generative organs in the fowl consist of two testicles
and an excretory apparatus, the vas deferens, for each.

The Testicles. Location.—The testicles are located in the sub-
lumbar region of the abdominal cavity, behind the lungs, below the
anterior extremity of the kidneys, and opposite the last three ribs.

Fic. 54.—The pelvic organs of a cockerel. A, Testes. B, Rectum. C, Cloaca.
D, Vas deferens. E, Kidney. F, Adrenal gland. G, Lungs. H, Ureter.

Shape.—The testicles are ellipsoid in shape; their size varies
with the different species of birds. The two in the same bird are
usually of the same size, though one testicle may be slightly larger
than the other. In a summary of a large number of weights of the
testicles of ten months old cockerels, the average weight was 0.021
pound each. The average measurements were 2 inches in the major
diameter and 1 inch in the minor diameter. In the cockerel before
sexual maturity, which is denoted by the male bird’s crowing, the

testicles are very small. They resemble, in shape, a navy bean and
are yellowish-white in color.

176 ANATOMY OF THE DOMESTIC FOWL

Structure-—The testicle is surrounded by a thin fibrous capsule,
which, in the mature cock, is very vascular. This capsule sends
into the interior of the gland, septa which form the framework,
or supporting structure. This framework forms the spaces in which
are located the glandular substance. The glandular portion consists
of the tubuli seminiferi, which are lined with cubical cells. The
framework supporting these tubules gives passage to arterial
branches of the spermatic artery, which furnish an abundant blood
supply; the framework also supports the veins returning the blood
from the testicle. The seminiferous tubules end in blind extremities
in the epididymus or globus minor, and unite in the seminiferous
canals. All arteries, veins, lymphatics, and seminiferous tubules
enter or leave through the globus minor at the attached portion of
the testicle. The epididymis is made up largely of convoluted
tubules which are the continuation of the secreting tubules of the
globus major. The walls of the tubules of the globus minor become
thicker and are provided with smooth muscle cells in addition to
the connective tissue and endothelial lining. The convoluted
tubules empty into the vas deferens. The epididymus is covered
by the fibrous capsule; which corresponds to the tunica albuginea
of mammals and may be considered as a reflection or modification
of the visceral peritoneum.

The substance of the testicle is very soft; in fact, it may be said
to be of the consistency of encephaloid material. It is made up
of secreting tubules in which are found the spermatozoa; it also
contains cells which produce an internal secretion, or hormone.
There is also produced some fiuid in which the spermatozoa float,
the whole material manufactured constituting the semen.

The spermatozoaof the fowl are provided with long cylindrical
bodies, which may be straight or wavy (Fig. 5 5, A). The body
of the spermatozoon is obtuse anteriorly, and posteriorly, tapers
into a filimentary tail, or flagellum, of varying length, by the aid of
which the spermatozoon moves about in the fluid.

The histological structure of the testicles of the baby chick at
hatching is approximately one-half white fibrous connective tissue.
The seminal tubules are small and widely distributed among the
connective tissue. The cells of these tubules possess rather large
nuclei, round in shape, with linin network and chromatin granules,
typical of resting germ cells. As the bird develops the testicles

THE URO-GENITAL SYSTEM 177

Fic. 55.
A. Spermatozoa of a cock. a, The spermatozoa. 6b, The head. ce, The tail.
B. The oviduct of a hen removed. A, The oviduct. B, The superior liga-
ment. C, The inferior ligament. Note the oviduct thrown in folds and the
anastomosing blood-vessels.
12

178 ANATOMY OF THE DOMESTIC FOWL

grow, the seminal tubules become larger, and the amount of con-
nective tissue correspondingly less.

In addition to the tubules, the spermatogenic cells, and the
connective tissue, there is also in the testicles more or less fat.
There is a small amount of connective tissue between the semi-
niferous tubules, in which locations there are also clusters of poly-
hedral cells, with round nuclei, others are the interstitial cells.

The Vas Deferens (Fig. 54, D). Location and Shape.—Extending
from the epididymus, is the vas deferens which runs backward
on the infero-internal surface of the kidney and to the outside of
the ureter. It is very tortuous passing on the infero-lateral surface
of the kidney in company with the ureter and becoming somewhat
expanded posteriorly it terminates in the upper wall of the cloaca
in a rather small papilla located in ‘the uro-genital portion of the
cloaca anterior to the mouth of the ureter. This papilla is the
organ of copulation and in ducks is very large, and spirally elongated,
and retractile forming a kind of penis. The papilla is traversed
by a furrow on the upper surface through which the semen flows.

Structure—The vas deferens is covered and supported by the
peritoneum. Its wall is made up of a fibrous structure in which
may be found smooth muscle fibers. The wall does not possess
glands. It is lined with columnar epithelium. The posterior
end is expanded and terminates into a papilla. The base of the
papilla is surrounded by a plexus of arteries and veins, which serve
as an erectile organ during the venereal orgasm, when the fossa
of the turgid papilla is everted, and the semen brought into contact
with the similarly everted orifice of the oviduct of the female,
along which the spermatozoa pass by undulatory movements of
their ciliary appendage, or tail.

THE FEMALE GENERATIVE ORGANS (Fig. 56)

The female generative organs consist of one ovary and an oviduct.

Location.—The ovary is located similarly to the testicles of the
male bird, in the sublumbar region of the abdominal cavity, just
at the anterior end of the kidneys, posterior to the lungs, and slightly
to the left of the center.

Shape.—In the pullet the ovarian mass appears somewhat like a
bunch of grapes, being made up of from 3500 to 4500 small, whitish
spheres, which represent the undeveloped ova, and which in the

THE URO-GENITAL SYSTEM 179

active state are developed, one by one, into yolks with their blasto--
derms. From the blastoderm the fetus may later be developed.
In the active ovary of the laying hen the ovarian mass is of consider-
able size, as it contains ova in different stages of development.
Only one ovum is completely developed at a time, though occasion-
ally there may be only a few hours between the maturity of succes-

Fic. 56.—Functionating female generative organs of ahen. 1, Ova in process
of formation of yolk. 2, Stigmal line at which point the capsule ruptures when
ovum is mature. 3, The funnel end of the oviduct. 4, The oviduct torn loose
and laid to one side, the albumin-secreting portion. 5, The shell membrane
secreting portion. 6, The albumin. 7, Fhe yolk. 8, The shell-secreting por-
tion. 9, Thecloaca. 10, The rectum.

sive ova. The ova réceives nourishment from the blood-vessels
‘of the capsule, which vessels are branches of the ovarian artery.
Structure —The ovary contains very vascular cellulofibrous tissue.
The ovum as it develops is attached to the ovarian body by means
of a delicate white fibrous pedicle. When the yolk is mature
it escapes from the enveloping fibrous capsule by a cleavage of
the capsule. The cleavage line is called the stigmen (Fig. 56, No.

180 ANATOMY OF THE DOMESTIC FOWL

2). . The yolk is surrounded by a very delicate membrane called the
vitelline membrane. The empty sac now shrinks and finally
disappears.

The Egg.—The principal divisions of the egg are the yolk, the
albumin outside of the yolk content, the shell membranes and the
shell (Fig. 58). As stated, the yolk is formed in the ovary, leaving
the other three portions to be formed in the oviduct.

Fic. 57.—Section through the ovary of the hen. u, The ova. d, An ovum
beginning to receive deposits of yolk material. c, Ova farther advanced in yolk
formation.

The albumin may be subdivided into, first, a thin layer of albumin
lying close around the yolk; second, a thick layer of albumin lying.
at the outer periphery; and third, a modification of the albumin
called the chalaze. The chalaze are twisted, dense cord-like
structures at either pole of the yolk, one end of which is adherent
to the vitelline membrane and the other to the inner membrane
surrounding the albumin. The chalaze thus act as stays to this
structure, which is carrying a delicate burden, the blastoderm.

THE URO-GENITAL SYSTEM 181

The shell membrane consists of two layers, an inner delicate,
and an outer thicker layer. When the egg is just laid these two
membranes are in all parts closely adherent to each other, and the
egg content completely fills the shell cavity. As soon as the content
cools there is a slight contraction; the two shell membranes separate
at the large end of the egg, forming an air cell which gradually
enlarges as the evaporation of liquid through the pores of the shell
takes place.

The shell consists of several layers. Three are easily distinguish-
able: first, an inner mammillary layer, consisting of minute conical

Fic. 58.—A diagram of the parts of the egg. «@, The blastoderm. 08, The
shell. c, The outer shell membrane. d, The inner shell membrane. ¢, The air-
sac at the large end of the egg. f, The albumin. g, The chalaza. h, The
yellow layers of yolk. i,’'The white layers of yolk. k, The flask-shaped portion
of white yolk. Jl, The vitelline membrane. :

deposits of calcareous material; second, a middle spongy layer,
composed of a thick network of fibers; third, an outer delicate,
cuticle-like structure. In certain breeds of poultry a pigment
may be added; for example, in ducks a pea green, in turkeys a
spotted brownish material, and in fowls pink and various shades of
brown. The egg shell is porous to admit the free exchange of air
during the process of incubation.

An average sized hen egg weighs about 2 ounces, of which 11
per cent. is shell, 32 per cent. yolk, and 57 per cent. white. The
principal ‘chemical constituents of the egg are as follows: ash, or
mineral matter, 9 per cent.; fat, or hydrocarbon, 9.3 per cent.;
proteids, or nitrogenous matter, 11.9 per cent.; and water, 65.5

182 ANATOMY OF THE DOMESTIC FOWL

per cent. There is apparently no constant proportion of weight
between the yolk and albumin. There is also a variation in the
weight of the shell due to its variation in thickness.

In an examination of ten eggs of average size, the yolk constituted
31 per cent. of the total weight of the egg.

The following is the result of the analysis of twelve eggs of average
size. This analysis included the shell and all other parts taken
together.!

MOIstttes cians iat orncaenaescans 64.25 per cent.
Dry Matte ha yce sy wise seg eee seme se 35-75 per cent.

100.00 per cent.

Parts per hundred including shell

PROC cc tins cane engiaceme eatdaune anne IO. 250¢
Pati ov decked Hoey yA EIRE SANS Sted OS ed 10.6200
Phosphorus 4ij.5.s.c.4 :sgio sae gaaiyicn sg aenlid wg 3020
Calcimicdeins yee ooe aha ni ate hades Hae rams . 6080
Moagneésiumss:. <i ie3sea seus ged izers tek betes 0935
DYOD, a cts ara siete b testasd aun pale naiaun paccuie wees Heel -O103
SUPHUP ase tne Rh eRaNs AAR oawes YORE - 3950
CHIGHHIE) spite ceqiemerraeanseras eRe eens . 1506
Potassium s0% het ensd Aue s bead by Ge Ae aes .O103
Sodium............ Sede wE mee her Sh wslatoms ees 2000

The Oviduct.—The three separate and distinct portions of the
egg, albumin, shell membranes, and the shell, are constructed in
different parts of the oviduct.

Location —The oviduct of the hen extends along the left side of the
bodies of the vertébre, and the roof of the pelvic cavity and lies
dorsal to the abdominal air-sac. It extends from the posterior
border of the ovary and empties into the cloaca (Fig. 56, No. 3 and
8) through a transverse slit.

Shape——In a well-developed Plymouth Rock pullet, but one
whose reproductive organs have never become active, the oviduct
is about 414 inches long; in the fully developed and active state it
is from 18 to 20 inches long, and in a collapsed state about 14 inch
in diameter. It is held in position by two ligaments, a dorsal and
a ventral (Fig. 55 B) to be described later. The oviduct is tortuous
in its course, forming three principle convolutions before reaching

1The analysis was made by D. M. McCarty, chemist, Animal Industry
Division, North Carolina Experiment Station.

THE URO-GENITAL SYSTEM 183

the cloaca, and like the cvarian mass, in its active state, pushes
the abdominal viscera downward and toward the right side.

Structure—The oviduct consists of three coats: first, the serous,
located on the outside, which is a reflection of the peritoneum;
second, the muscular middle tunic; third, the mucous coat, which
in a resting state is thrown into folds.

Fic. 59.—The active oviduct of a hen laid open. 1, The ovary. 2, The
funnel. 3, The albumin secreting portion. 4, Theisthmus. 5, The shell gland
portion. 6, The vagina. 7, The superior ligament. ‘ 8, The inferior ligament,

Parts of the Oviduct.—The parts of the oviduct are as follows:
the funnel, the albumin-secreting portion, the isthmus, the shell-
gland portion, or uterus, and the vagina (Fig. 59).

The funnel is the trumpet-shaped portion, the ostium tube
abdominale, whose mouth or fimbriated opening faces the ovary,
and lies ventrally to receive the ovum, or yolk, as it is discharged
from the ovary. Its thin wall, expanded in the anterior portion,
is provided with fimbrie-like projections. This funnel-shaped
portion soon converges to form a constricted portion. This por-
tion of the active oviduct is from 3 to 4 centimeters long. The
mucous membrane occurs in folds forming low longitudinal spiral

184 ANATOMY OF THE DOMESTIC FOWL

ridges (Fig. 60, A). The fimbriz are continuous with the dorsal
and the ventral ligament of the oviduct; and from this point,
where the ridges of the mucous membrane are almost nil, they
gradually increase in height as they extend down the tube. These
ridges are continued in those of the second, or albumin-secreting
portion (Fig. 60, D). At this point they increase in height very
rapidly. Here the bundles of muscular fibers of the middle coat
are thin and distributed among bundles of connective tissue. The
muscular fibers consist of two layers, an outer longitudinal and an

Fic. 60.—The mucous lining of the oviduct.

A. Transverse section of the oviduct wall in the region of the neck of the
funnel showing primary and secondary folding of the epithelium (after Surface).

B. Showing the type of gland cells of the funnel region.

C. Transverse section through the wall of the uterus showing the deep folds..

D. Section from the albumin-secreting portion showing the opening of a.
tubular gland and also showing the character of the cells.

inner circular. At places in this portion the inner bundles may
be noted to extend longitudinally. In embryological development.
the epithelial layer has an origin different from the outer layers of
the oviduct. In the fetal development the Miillerian duct arises.
as a thickening along the Wolffian body just ventral to the gonad.
This Miillerian duct is at first a solid cord of cells. It later develops.
a lumen, and grows posteriorly until it connects with the cloaca.
At the time of this posterior growth, mesenchyme cells migrate
in from the surrounding tissue and form a layer about the duct.
From this layer of mesenchyme cells there are developed the outer

THE URO-GENITAL SYSTEM 185

layers of the oviduct, which layers later develop the muscular
structure and the connective tissue. The epithelium and its
derivatives, which represent the glandular structures, are formed
from the walls of the old Miillerian duct. Thus the two sets of
tissues, having different origins, likewise have different functions.
The epithelium is concerned entirely with secretion, and the deriva-
tives of the mesenchyme are con-
cerned with supporting and muscu-
lar function.

To summarize, six layers of tissue
occur in the funnel region, namely,
an outer serous covering, an outer
longitudinal muscular layer, a layer
of connective tissue, an inner circular
layer, a second layer of connective
tissue, and an inner mucous layer.
The mucous layer is made up of.
glands, as follows. The unicellular
glands occur between the ciliated
cells of theepithelium. These glands
are found only in the posterior half
of this division of the oviduct. The
glandular grooves are made up of an
accumulation of gland cells at the
bottom of the grooves between the
secondary folds of the epithelium.
These are found in all parts of this Fic. 60, A.—The mucous lining of
division except the extreme posterior She ovadutte
part. In the posterior part-we find E. Section of the epithelium

from the vagina showing unicellular

the third type of glands, the tubular glands.

5 F. A section from the isthmus
variety. showing opening of a tubule.
The second division of the oviduct,

as stated above, is the albumin-secreting portion. The funnel divi-
sion gradually merges into the second portion. These two portions
are distinguishable from each other. The walls of the albumin-
secreting portion are much thicker and the longitudinal ridges are
higher. This section is the longest of the five divisions, measuring
from 40 to 42 centimeters in length, or more than half the length
of the oviduct. The albumin division terminates rather abruptly
into the third division, the isthmus (Fig. 59, A).

186 ANATOMY OF THE DOMESTIC FOWL

It is probable that the secretion of albumin is not confined to the
cells of the second division; yet we are safe in saying that the major
portion is formed here. The folds of mucous membrane in this di-
vision are thicker and higher than in the funnel, due to their con-
taining cells of the high columnar type, and to the fuller development
of the glands which are of the tubular variety. The muscular layer
is heavier, and therefore the muscular power to force along the
tubes’ contents is greater. In the formation of the mucous folds we
find, in transverse sections, that the central core is made up of con-
nective tissue which carries blood-vessels and nerve filaments, as
in other similar glandular structure. The epithelium contains glan-
dular cells of two varieties, namely, the ciliated, columnar variety,
and the unicellular, goblet variety (Fig. 36, No. B, 2). These two
kinds of glandular cells are rather evenly distributed throughout the
epithelium of this section of the oviduct. The unicellular gland cells
are more numerous at the mouths of the ducts leading from the tu-
bular glands. The nuclei of the ciliated cells: are oval and lie near
the middle of the cells or a trifle toward the base from the middle.
The protoplasm of the cells is finely granular. Strong cilia in con-
siderable number surmount each cell. In some cases the goblet or
mucous cells have pushed apart the ciliated cells, and their prolon-
gations extend farther than the surface of the ciliated cells. The
nuclei of the goblet cells are round, and lie nearer the proximal
end than those of the ciliated cells.

The third division of the oviduct, the isthmus, continues from the
albumin-secreting portion and terminates in the expanded portion
called by some anatomists, the uterus. Toward the posterior
end of the albumin-secreting portion the longitudinal folds. of mu-
cous membrane become lower, making, at the juncture of this and
the isthmus, a clear line of demarcation. For a distance of 2
or 3 centimeters the folds are low, after which they gradually
become higher, but never reach the height or thickness of those in
the albumin-secreting portion.

The clear-cut line between the albumin-secreting portion and
the isthmus is partly due to a zone in which the long tubular glands
are lacking. The core of the folds of mucous membrane in this
zone contain much more connective tissue. The cells are both
ciliated and unicellular. The rest of the histological structure of
the isthmus is the same as that of the albumin-secreting portion.

THE URO-GENITAL SYSTEM 187

The function of the isthmus is to secrete, or to form, the shell
membrane, the membrana testacea. . ,

The fourth division of the oviduct is the werus, or the shell-gland
portion (Fig. 60, C). There is no clear line of demarcation between
the isthmus and shell-gland portion, the walls gradually expanding.
In this region the folds of mucous membrane become leaf-like and of
considerable length, extending into the lumen, thus affording a
greater cellular surface. The same coats of the duct are present
here as in other parts; but the outer longitudinal muscular layer is
thicker and possesses more strength. The quantity of connective
tissue is about the same. The glands are of a tubular type and the
same two varieties of epithelial cells are found here as elsewhere,
namely, the ciliated high columnar and the unicellular mucous
variety.

In the active glandular cells of the shell-forming region the nuclei
are small, dark staining, and lie toward the center of the cell. The
chromatin granules and nucleoli take on a comparatively deep basic
stain, but they do not show the intense stain found in the albumin
and the isthmus region. The cytoplasm of the uterine tubular
glands does not present as heavy a granular appearance as that of
the albumin portion. These cells are diffusely granular, the granules
appearing of one size and taking the stain faintly. The function
of this portion is to secrete, or form, the hard calcareous covering
which has been described at the beginning of this section.

The fifth division of the oviduct is the vagina. There is located,
at the juncture of the shell-gland portion with the vagina, a strong
sphincter-muscle. The vagina is that constricted portion of the
oviduct extending from this muscle to the cloaca. The mucous
membrane forms low narrow folds with secondary folds, which
appear continuous with those of the shell-gland portion. The core
of these folds is composed of connective tissue. The vagiria in
the hen of average size measures from 12 to 13 centimeters long
(Surface). The inner or circular muscular layer is well developed;
it is much thicker than in any other part of the oviduct. This
extra development gives the power necessary to successfully expel
the egg. The outer longitudinal layer is not-so well developed; its
bundles are scattered throughout the connective-tissue layers. The
egg is caused to move along in the oviduct by a successive series of
contractions of the circular muscular fibers posterior to it. There
are no tubular glands in this portion, but a simple layer of high

188 ‘ANATOMY OF THE DOMESTIC FOWL

ciliated columnar epithelium, and some goblet, or mucous cells.
The cells on the surface generally are long and slender; in the grooves
between the mucous folds the cells are shortest, reaching their
greatest length at the tops of the folds.

The function of the vagina is the secretion, or formation, of the
outer shell cuticle commonly called the bloom, and also in certain
breeds, as indicated above, the tint.

The cloaca furnishes a passage way from the vagina to the ex-
ternal world by way of the anus. The walls of the cloaca contain
glands. :

The Ligaments of the Oviduct.—It is held in position by two
ligaments, one dorsal and one ventral. The dorsal ligament of the
oviduct is formed by a double layer of peritoneum with a very
small amount of connective tissue interposed. The peritoneum is
also reflected over the oviduct. The-ventral ligament of the ovi-
duct is narrower than the dorsal, but is similarly constructed. Both
ligaments are rather ‘veil-like in appearance. During the first four
or. five months of the growth of the young female fowl the develop-
ment of the oviduct and its ligaments is in proportion to that of the
body. With the elongation that takes place about the time of func-
tionation, as described above, the ligaments enlarge in proportion
to the enlargements of the oviduct. The dorsal ligament maintains
a line of attachment to the body wall from the caudal end of the body
cavity to the fourth thoracic rib. The ventral ligament elongates
only slightly during this developing period. It becomes thicker
and stronger and early develops a muscular coat. It also grows in
width except at the caudal end. At this point the ligament is
simply a mass of muscular tissue of the smooth or involuntary type.
These ligaments are fan-shaped.

The muscle fibers of the dorsal ligament of the laying hen, have
their origin in a line near the medial side of the dorsal margin. At
this point the bundles of fibers are quite thick, but are spread out
thinly toward the margin of the oviduct. Frequent anastomoses are
noted. The muscular fibers become continuous with the circular
ones of the oviduct.

The ventral ligament of the oviduct of the laying hen is largely a
muscular cord 3 to 6 centimeters in diameter. The caudal end
is thicker, becoming gradually thinner toward the anterior portion.
The bundles of muscular fibers extend toward the oviduct blending
with the circular fibers of that viscus. The ligaments terminate

THE URO-GENITAL SYSTEM 189.

anteriorly in such a manner that they aid in forming the serous
ovarian pocket, which guides the yolk into the fimbriated portion,
or funnel, of the oviduct. The walls of the ovarian pocket are
formed by the left abdominal air-sac, a part of the intestine, and
the mesentery. The dorsal portion is formed by the roof of the
abdominal cavity, and the ventral portion is formed by the dorsal
wall of the air-sac. The medial, the anterior, and the lateral limit
of the pocket are formed by a fusion of the wall of the air-sac to
the mesentery and to the body wall. Posteriorly, the wall consists
of the transverse part of the small intestine and the caudal portion
of the left cecum with their attached mesentery.

THE DUCTLESS GLANDS

These glands do not possess excretory ducts. They furnish
materials which are added to the blood or lymph as it passes through
them. The material from each gland is known as an internal se-
cretion, or hormone. Some of these secretions are powerful ma-
terials and influence profoundly the body nutrition. The ductless
glands are usually given as follows: the spleen, the lymph glands,
the pineal gland, the pituitary body, the thyroid gland, the thymus
gland, the adrenal glands, and the parathyroids. The spleen, the
pituitary, the pineal, and the lymph glands are described in other
sections.

The Thyroid Gland (Fig. 21, No. 16). Location—The thyroid
gland lies on the ventral side of the carotis communis at a point
where the carotis communis touches the jugular vein, which is about
the point of origin of the vertebral artery.

Shape.—The thyroid gland is small, oval or somewhat roundish,
and red or rose-colored.

Structure—The thyroid gland has a fibrous capsule, which sends
into the interior septa which divide it into acini. These acini are
closed and contain a fluid. The thyroid is a ductless gland. Short
arteries from the carotis enter this gland, and some large veins con-
nect it with the jugular vein. The lymph vessels which lie along the
neck are closely connected with it and receive twigs from the gland.
The minute lymphatic capillary endings are found in its septa and in
its capsule. The acini are lined with a single or a double row of
cuboidal secreting cells. There are two kinds of cells, namely,
secreting and resting cells. The actively secreting cells secrete
colloid.

The parathyroids consist of two small bodies attached to the
lower pole of the thyroid.

The Thymus Gland (Fig. 47, No. 10).—The thymus gland is an
organ of fetal and early baby chickhood. It soon undergoes retro-
gressive changes into fat and connective tissue. It is of epithelial

190

THE DUCTLESS GLANDS Ig!

origin, being formed in fetal life from the entodermal cells of the dor-
sal end of the throat fissure.

Location.—The thymus gland lies anterior to the thyroid, the
latter lying the deeper.

Shape.—The thyroid consists of two lobes, which are united by
connective tissue, and appears as a loop-like acinous gland lying
along the neck and near the region of the bronchi and the jugular
veins with fibrous extensions toward the head.

Structure.—The gland lobes are divided into lobules, which con-
sist of a cortical and a medullary portion. The cortex consists
of nodules of compact lymphatic tissue similar to those found in the
lymph glands. These occupy the chambers formed by the septa
of connective tissue. In the medulla there are a number of spherical,
or oval bodies composed of concentrically arranged epithelial cells.
These are known as Hassall’s corpuscles, and represent only the
remains of the original glandular epithelium. They are charac-
teristic of the thymus~gland. The thymus appears to be a type of
lymph organ. Lymph vessels are rare; a few blood-vessels on the
‘upper side form: capillary nets.

The Adrenal Gland (Fig. 54, F). Location.—The adrenal gland,
often called the supra-renal capsule, lies just anterior to the front
part of the anterior lobe of the kidney, adjacent to the testicles in
the male and to the ovary in the female. It is loosely attached by
connective tissue to the posterior aorta and to the vena cava.

Shape.—It is yellowish-brown or reddish-pink in color, small,
and of irregular formation.

Structure-—The adrenal gland consists of a cortical and a med-
ullary portion, although these two parts are not distinctly marked.
The cortical portion has columns which extend deeply into the gland,
and the medullary portion sends columns into the cortical portion.
Therefore, the two substances, lying side by side, form a cord-like
structure.

It is probable that the cortical portion is derived from the in-
growths of the peritoneum, and the medullary cords from the sym-
pathetic ganglion.

The cells are cylindrical or polygonal in shape, with an eccentric
substance between the columns. The cords, or columns, form be-
tween them, elongated channels which extend into the interior of
the gland and end as blind or cecal extremities. Large ganglionic
nerve cells belonging to the sympathetic system occur near the sur-

192 ANATOMY OF THE DOMESTIC FOWL

face of the gland. The blood-vessels aré not well developed in the
interior of the gland but are numerous and of good size in the outer
parts. Lymph vessels are also present.

Function.—The adrenals are ductless glands. They secrete an
internal secretion, or hormone, which influences the tonus of the
blood-vessels. An extract: from these glands is called adrenalin.

THE RESPIRATORY APPARATUS (Figs. so and 61, A)

Owen says: “Notwithstanding the extent and activities of the
respiratory function in birds, the organs subservient thereto mani-
fest more of a reptilian than of the mammalian type of formation.”

By the action of the respiratory organs certain chemical and
physical changes take place in the blood. The chief of these con-
sists in absorption of oxygen from, and giving off carbon dioxid
to, the atmospheric air, the former changes being necessary for the
elaboration of the fluid, the latter for the elimination of a substance
which, if retained, would prove injurious. The organs of respira-
tion are invariably adapted to the wants of the animal and the me-
dium in which it lives.

In the bird, which breathes through its nose, the organs of respi-
ration are nostrils, nasal chambers, pharynx, superior larynx, tra-
chea, inferior Jarynx, bronchi, bronchial tubes, lungs, and air-sacs.

The Nostrils and the Nasal Chambers.—The nostrils of the bird
open externally by two small elliptical openings, which pierce the
upper mandible. Within each nasal chamber (Fig. 26, A) are three
turbinated lamine, or-turbinated bones. The inferior one is‘a sim-
ple fold adhering to the lower and anterior part of the nasal septum.
The middle turbinated bone is the largest. It is of infundibular
form, and adheres by its base to the septum and externally to the
side wall of the nose. It is convoluted with two and a half turns.
The superior bone, of bell shape, adheres superiorly to the frontal
bone. The internal turbinated bone extends toward the orbit;
the external terminates in a cul-de-sac behind the middle turbinal
(Fig..26, No. A, 1 and 2, and G).

The nostrils are separated by a partition which is partly bony and
partly cartilaginous. The posterior nares is represented by a long
slit in the hard palate.

The Pharynx and the Superior Larynx.—A transverse row of
horny, filiform papilla marks the anterior border of the pharynx,
where in other animals the soft palate, or velum, is located. (For
further description of the pharynx see special chapter.)

The supero-posterior border of the larynx, at the juncture of the

13 ’ 193

194 ANATOMY OF THE DOMESTIC FOWL

larynx and the esophageal margin, is marked by a second transverse
row of horny, filiform papilla, which point backward. There is
no epiglottis. The superior part of the larynx is pierced by an oval,
slit-like opening, the glottis, which is provided with two lips. These
when brought together, tightly close the glottis so that nothing can
fall through into the larynx in the act of deglutition. The margin,
or rim, of this opening is called the rami glottis. The glottis is con-
trolled by two pair of muscles.

The superior surface of the larynx is somewhat triangular with the
apex directed forward. A few delicate, filiform papilla are upon .
its surface. The bird has, as already indicated, two larynxes, the
superior larynx located at the upper end of the trachea, and the
inferior larynx at the bifurcation of the trachea. The inner sur-
face of the superior larynx is smooth and does not contain vocal
cords; it is in these animals simply a passage for air. It is joined
to the trachea inferiorly by a ligament, the crico-trachealis, and lies
at the base of the tongue supported by two cornua of the os hyoideum.

The cartilages forming the principal support of the superior larynx,
consist of four pieces, as follows: one unequal ventral piece, two side
pieces, and one unequal dorsal piece. The cartilaginous, flat,
ventral cricoid, early in the bird’s life, often becomes bony. The
side pieces are separated from it, only exceptionally fusing with it.
The dorsal cricoid piece also often becomes bony. The two aryte-
noid cartilages, joined with the cricoid superiorly, are three-sided,
and are united to each other in a sharp angle. They form the su-
perior opening of the superior larynx.

The Trachea.—The trachea is cylindrical and varies in length in
different kinds of birds in accordance with the length of the neck.
It consists of from 90 to 120 cartilaginous rings, complete with the
exception of the two uppermost, which rings are held together by
intercartilaginous ligaments. The tracheal rings are constructed
of hyaline cartilage and the ligaments of fibrous tissue. It is lined
with a mucous membrane covered by columnar epithelium. The
trachea is a passage for air alone and terminates in the inferior
larynx.

The Inferior Larynx.—The inferior larynx, called the true larynx
because it is the organ of voice, is located at the inferior end of the
trachea and the superior ends of the bronchi. By some anatomists
this organ has been called the larynx broncho-trachealis. The larynx
is flattened laterally in fowls. It contains two membranous folds,

THE RESPIRATORY APPARATUS 195

which in the production of sound are caused to vibrate. These folds
are half-moon shaped elastic structures, located in the bony, arrow-
like way, intero-inferiorly. These structures are called the membrana
tympana interna. In the duck this inferior larynx is represented by
a drum-like cartilaginous and bony structure, called the bulla tym-
paniformis. This bulla is a resonant apparatus which serves to
“strengthen the voice.

In song birds there is a double glottis, usually produced by a
bony bar, called the pessulus, or os transversale, which traverses the
lower end of the trachea from front to rear. It supports a thin
membrane which ascends into the tracheal area, and, terminating
there by a free concave margin, is called the membrana semi-lunaris.
This is most developed in singing birds, and being vibratile, forms
an important part of their trilling vocal apparatus. The air passes
on each side of the membrana semi-lunaris and its sustaining bone to
and from the bronchi and lungs. ;

The last ring of the trachea usually expands as it descends, with
its fore and posterior parts produced, and the lower lateral borders
concave; the extremities of. the: pessulus, butts against the angle
thus formed and expands to be‘attached, also with the fore and pos-
terior terminations of the first half ring of the bronchus, strength-
ening and clamping together the upper part of the vocal framework.
The second bronchial half ring is flattened and curved with the con-
vexity outward, like the first, but is more movable. The third
half ring is less curved and further separated from the second, to
the extremities of which its own are connected'by a ligament, and,
for the intervening extent, by a membrane; its inner surface supports
the fibrous cord, or fold, which forms the outer lip of the glottis
of that side; it is capable of rotary movements on its axis, and is
an important agent in the modulation of the voice. All these
parts just described are bony.

The Bronchi and the Lungs.—The bronchi, two in number,
are provided with only incomplete cartilaginous rings. They enter
the inferior face of the lungs, toward their anterior and middle
thirds and break up into primary bronchi, which give off at right
angles, secondary bronchi, and these latter in turn give off tertiary
branches.

The lungs occupy only about one-seventh of the thoracic space.
They are long, flattened, and oval, extending along each side of the
spine from the second dorsal vertebra to the anterior end of the kid-

196 ANATOMY OF THE DOMESTIC FOWL

neys, and laterally to the juncture of the vertebral with the sternal
portions of the ribs. They present two faces, a superior convex and
an inferior concave; two borders, an external and an internal; and two
extremities, an anterior and a posterior (Fig. 61). The convex sur-

Fic. 61.—The lung:

A. The outer surface of one lung. Note the flattened oval shape. It is not
divided into lobes. 1, The bronchus. 2, Primary tubules showing openings
leading from the primary tubules to the secondary tubules. 3, Openings of two
of the large tubes into the diaphragmatic and abdominal air-sacs.

B. Sectioned surface of lung. 1, Secondary tubules. 2, Tertiary tubules.
3, Interlacing capillaries and air cells.

C. 1, Cavity of tubule. , Its lining membrane supporting blood-vessels with
large areole. 3, -Perforations in the membrane at the orifices of the lobular
passage. 4, Interlobular space containing the terminal branches of the pulmo-
nary vessels supplying the capillary plexus, 5, 5, to the meshes of which air gets
access by the lobular passage.

face is also called the dorsal, costal, or superior face. It is moulded
on the walls of the thorax and occupies a part of the intercostal
space, pushing the intercostal muscles outward. When the surface
of the lung is examined it is seen to be furrowed where the ribs
pressed during life. These furrows are as deep as the ribs are

THE RESPIRATORY APPARATUS 197

thick. The sides of the lungs are covered with connective tissue
which attaches them to the costal walls.

The concave, or inferior, face also called the diaphragmatic or
visceral face is directed downward. The diaphragm separates it
from the abdominal viscera. The surface is covered by connective
tissue which closely attaches it to the diaphragm. It is perforated
by the five tubules which bring the posterior air-sac into communi-
cation with the lungs. :

The borders of the lungs extend parallel to the long axis of the
body. The internal border is rectilinear, thick, and rounded. The
external border is convex, thin, and sharp.

The anterior extremity terminates in a sharp point which occupies
a space formed by the ribs externally and the inferior spines inter-
nally. The posterior extremity is somewhat rounded and extends
as far back as the anterior border of the kidneys.

As soon as the bronchi enter the lungs they become broadened,
the cartilaginous rings disappear, and they continue as membranous
channels whose diameters gradually decrease, as they extend back-
ward, to the point where they terminate in the ostium caudale, at
which point they are surrounded by a cartilaginous ring. The
ostium caudale brings the tubules into communication with the
ventral air-sacs.

Twelve air tubules have their origin from each common bronchus,
or trunk. Four are given off from the interna] wall of the main
bronchus by a series of openings arranged in arow. Seven are given
off from the external wall by a second series similar to that of the
first. The twelfth extends from the inferior wall, and immediately
takes a course downward and outward and communicates with the
posterior diaphragmatic air-sac. This may be considered as the
terminal branch of the trunk.

All of these secondary canals, except the last, pass toward the
periphery of the lung. They divide and subdivide at the periphery,
covering it with their ramifications. The canals extending from the
inner wall are distributed to the inferior face of the lung. Those
extending from the outer wall are distributed to the outer face of the
lung. The first constitute the diaphragmatic and the second the
costal bronchial tubes.

The four diaphragmatic bronchial tubes are numbered in the order
in which they are given off.. Thefirst is carried forward horizontally,
the second transversely inward, the third obliquely inward and back-

a
198 ANATOMY OF THE DOMESTIC FOWL

ward, and the fourth directly backward. They have, by some
anatomists, been called the anterior, the internal, and the pos-
terior diaphragmatic bronchial tubes. There are two posterior
diaphragmatic bronchial tubes; the larger called the great pos-
terior, and the smaller, which passes directly backward, the small
posterior.

The costal bronchial tubes, seven in number, are numbered from
the front backward in the order they are given off. Parallel at
their origin, and side by side, like pipes of an organ, they soon spread
out in fan shape like the preceding. They extend from their cen-
tral origin to the periphery. The first extends obliquely upward
and inward to the anterior extremity of the lung. All branches
from this bronchus extend from its anterior wall. The first branches
are inflected to reach the external border of the lung. The succeed-
ing branches are directed forward and the last forward and inward.
They all meet those from the anterior diaphragmatic bronchus,
but do not anastomose with them.

The second, the third, and the fourth costal bronchi extend in a
transverse manner and ramify on the inner border of the lung.

The fifth and the sixth are directed toward the posterior extremity
of the lung. The seventh, very small, reaches this extremity, where
it disappears.

The first costal bronchus is the largest; those following it gradually
become smaller. At their points of origin they adhere closely to
the ribs. They are all imperforate, which is a distinguishing fea-
ture from those occupying the opposite face.

‘The canaliculi or tertiary tubules given off by these secondary
bronchial tubes do not differ greatly in caliber in the various parts.
They are given off at right angles from the pulmonary wall of each
bronchus, and extend perpendicularly into the lung substance.
Thus we find three kinds of conduits, the primary, the secondary,
and the peripheral, or tertiary. The first are like the barbs of a
feather on its shaft; and the second, and parenchymatous are im-
planted on the pulmonary walls of the first, like the hairs of a
brush on their common base. Thus instead of the branching of
the bronchi being dichrotomous, as in mammals, it is piniform.

The canaliculi, or finer tubules, communicate with one another.
The inner microscopic appearance of the canaliculi indicate that
they are divided into areola, which gives them a cellular aspect
These tertiary bronchi open on a dense labyrinth of blood capillaries

THE RESPIRATORY APPARATUS 199

(Fig. 61, C). At this point the ciliated epithelial cells give way to
simple squamous epithelium.

Thus we find three kinds of bronchi, or their ramifications, as
follows: the primary, the secondary, and the tertiary.

The Air-sacs (Fig. 61, A).—The air-sacs are bladder-likestructures
consisting of a delicate cellulo-serous membrane, an extension from
the bronchial tubes, in some places strengthened by an external
envelope of elastic fibrous tissue. Long thin blood-vessels are dis-

6

Fic. 61, A.—Diagram of air-sacs and their location. 1, The proximal end of the
humerus. 2, The proximal end of the right clavicle. 3, The cervical air cell.
4, The right coracoid bone. ' 5, The anterior thoracic‘air cell. 6, The right side
of the sternum. 7, The right side of the liver. 8, The peritoneum. 9, The
right abdominal air cell. 10, The coccyx. 11, The proximal end of the right
femur. 12, The right supero-posterior air-sac. 13, The right infero-posterior
air-sac. 14, Therightlung. 15, The axillary extension of the air-sac. 16, The
obturator foramen, 17. The pelvis.

tributed in the substance of these walls. They are branches from
vessels of the general circulation and not extensions from those of
the lungs. No lymphatics have been found in the air-sacs.

These sacs do not communicate with each other and normally
they are not fully inflated. In some locations they extend into the
bones and are in communication with the extensions of the bronchial
tubes. In fact, by some anatomists they have been called ‘‘bladder-
like, extra-pulmonary expansions of the bronchial tubes, free from
cartilage.” The air-sacs make the bird’s body lighter, thus making

x

200 ANATOMY OF THE DOMESTIC FOWL

long-continued flight possible. They are best developed in those
birds which fly most. There are four pairs of cells and one single
cell from which all other expansions and extensions are made.
‘These sacs are as follows: a single anterior thoracic, and, in pairs,
cervical, anterior diaphragmatic, posterior diaphragmatic, and
abdominal.

The Anterior Thoracic Air-sac.—The anterior thoracic air-sac is
located above the clavicles and the interclavicular space, in the
cavity of the thorax. It is related superiorly with the trachea and
the esophagus; laterally with the lungs and the cervical air-sacs;
inferiorly with the. sternum, the clavicle, and the interclavicular
aponeurosis; posteriorly with the heart and the anterior diaphrag-
matic reservoir; and anteriorly with the integuments of the neck.
It contains the inferior larynx and the two primary bronchi, and
large vascular trunks from which are given off vessels supplying the
neck and the wings.

Three prolongations, called subpectoral, subscapular, and middle,
or humeral, arise from the lateral walls of this air-sac. These
prolongations cross the walls of the thorax and pass around the
articulation of the shoulder.

The subpectoral prolongation extends from the thoracic reservoir
by an orifice situated behind the coracoid, and passes beneath the
tendon of the great pectoral muscle. When the pectoralis major
contracts, this contraction dilates the subjacent cell and draws into
it a greater quantity of air.

The subscapular and the humeral prolongations communicate with
the thoracic air cell by a common opening situated behind the small
adductor muscle of the humerus. The subscapular prolongation,
after leaving this point, spreads under the scapular and the sub-
scapular muscle, which it separates from the ribs and corresponding
intercostal muscles, and extends in.a longitudinal direction.

The humeral prolongation, smaller than the subscapular, occupies
the axilla, and is in shape triangular. It has from its summit into
an infundibular fossa, an extension which enters the canal of the
humerus. The walls of this cell form the lining of the air space in
the humerus.

The thoracic air-sac thus possesses numerous membranous folds
which divide its cavity. The contiguous structures which it over-
lies, as the trachea, the esophagus, the muscles of the inferior larynx,
as well as the arteries and veins, make its outer walls irregular.

This orifice is dilated during inspiration, by the contraction of the
two first fasciculi of the diaphragm.

The Cervical Air-sacs—The two cervical air-sacs are located just
above the thoracic air-sac at the inferior part of the neck and in
front of the lungs. They are cone-shaped with the base directed
forward and the apex backward. They are related superiorly with
the cervical muscles, and inferiorly with the thoracic air-sac from
which they are separated by the trachea, the esophagus, the pneu-
mogastric nerve, and the jugular veins. The walls touch each
other internally, and form a median septum which includes in
its substance the two common carotid arteries. Externally they
are related to the origin of the cervical nerves, to each of which they
contribute a small sheath. They surround the vertebral artery,
and are connected with the subcutaneous muscles and the skin.
The summits communicate with the anterior diaphragmatic bron-
chus. Prolongations extend from their bases which conduct the air
into all the vertebrz of the neck and the back, into all the vertebral
ribs, and into the spinal canal. Parallel with and adjacent to the
vertebral arteries, and lodged in the canals excavated in the trans-
verse processes of the cervical vertebre, are two cervical prolonga-
tions, one on each side, which extend to the cranium from the base
of the cervical reservoirs. From their sides, at the last six cervical
vertebra, are six extensions in the form of diverticuli, which,
lying against each other, pass from each side into the muscles of the
neck. They are surrounded by a thin fibrous envelope, a continua-
tion of the mucous lining of the sac, and apparently form a canal in
the inferior part of this region. These prolongations are better
developed in palmipedes than in chickens. On the internal side
of these prolongations, one or more foramina penetrate the vertebral
segment, which allow the extensions of the prolongations into the
spinal canal. Chauveau states that “as the medullary tissue is
replaced by air in the bones of birds, so is the subarachnoid fluid
replaced by air around the spinal cord.”

The prolongations extending from the cervical air-sacs, having
entered the thorax, terminate by passing into the first dorsal verte-
bra. After permeating every part of this vertebra, it escapes by a
lateral opening and forms a small sac located between the first two
ribs, near the origin of the first dorsal nerve. From this sac an

202 ANATOMY OF THE DOMESTIC FOWL

extension is given off, which enters the second vertebral segment at
the antero-lateral part; from this point it passes back, forming a
new air-sac between the second and third ribs. It now passes in
the same manner into the third vertebra and extends through the
third intercostal sac, and so on till the last dorsal vertebra has been
served. At the same time that these sacs receive the air from the
vertebre preceding them, and transmit it to those which follow,
they communicate it to all the vertebral ribs. The aerial currents
which leave the cervical air-sacs do not communicate with those
of the cranium. Experiments show that the cranial bones have
apparently no communication with the respiratory apparatus.

The Anterior Diaphragmatic Air-sac——The two anterior dia-
phragmati¢ or supero-posterior air-sacs are related with the lungs
anteriorly, and with the abdominal viscera posteriorly. Anteriorly
also is the thoracic air-sac, posteriorly are the posterior diaphrag-
matic air-sacs, and laterally the’ ribs and the intercostal muscles
and internally isthe esophagus. The lungs communicate with these
air-sacs through circular openings from the great posterior diaphrag-
matic bronchus and frequently by a second opening from this same
tube. These are the only sacs which receive air from the lungs
through two openings.

The Posterior Diaphragmatic Air-sac——The two posterior dia-
phragmatic, or infero-posterior air-sacs are oval in shape and located
between the thoracic and the abdominal cavity. They are related
anteriorly with the anterior diaphragmatic air-sacs. These two
sacs form a vertical transverse partition. The posterior diaphrag-
matic air-sacs are related posteriorly with the abdominal air-sacs
from which they are separated by the diaphragm. They are
related below with the lateral parts of the sternum and the sternal
ribs, and externally with the ribs and the intercostal muscles.
These air-sacs communicate with the lungs through openings located
in the middle part of the external border of the lung, into the
extremity of voluminous bronchial tubés which follow the direction
of the largest air tubes.

The Abdominal Air-sacs—The two abdominal air-sacs located
on each side of the abdominal cavity, when inflated with air, form
enormous bladder-like structures. They are related laterally with
the abdominal wall and internally with the abdominal viscera. The
anterior extremities are in communication with the mesobronchi
and are somewhat inflected to pass under the fibrous arches extend-

THE RESPIRATORY APPARATUS 203

ing from the spine to the pelvis. Anteriorly these sacs adjoin the
diaphragm, the testes in the male, and ovary in the female, and to
the parietes of the abdomen and those of the pelvis. Below and in
front, they rest on a fibrous septum, which in all birds divides the
abdominal cavity into two smaller cavities: one anterior, represent-
ing the abdomen and containing the liver; the other posterior,
representing the pelvis and containing the gizzard and the intestines.
The anterior portion overlies the posterior part of the lobes of the
liver, the proventriculus, the spleen, and the gizzard. The kidneys
are located above these air-sacs. Dorsal to the sacs is also a part of
the intestines and in the female the oviduct. The abdominal air-
sacs are attached by a ligament-like structure in their medial, their
anterior, and their lateral margin. The posterior, the dorsal, and
the ventral margin are free. Mesially this attachment is to the
mesentery, connecting the left cecum to the dorsal margin of the
gizzard, and also to the mesentery of the proventriculus. The
anterior attachment is to the body wall and extends in front of the
end of the ovary and the adrenal glands. At the antero-lateral part
of the body cavity the attachment extends in a widening band along
the lateral side of the ovary and of the oviduct, as far back as the
caudal margin of the sac. The lateral attachment is related to
the kidney, the dorsal ligament of the oviduct, and the abdominal
wall.

Each of these abdominal sacs has three extensions: one supra-
renal and two femoral.

The suprarenal extension leaves the principal sac at the postero-
external part of the kidney, extends upward, and forward, and
expands over the surface of the kidney. At the internal border of
the kidney, this prolongation extends between the transverse
processes of the sacral vertebra, reaches a height of the first dorsal
vertebra, forms a triangular canal located above the sacrum in
the sacral channel, and is separated from its fellow by a series of
corresponding spinous processes.

The two femoral extensions, an anterior, small, and a posterior,
large, extend from the abdominal air-sac at the cotyloid cavity, leave
the pelvis through the bony passage occupied by the crural vessels,
extend around the coxo-femoral articulation, and terminate in a
blind extremity. In some birds, particularly in birds of prey and
ostriches, there are prolongations extending into the femur, entering
through a foramen at the anterior part of the great trochanter.

204 ANATOMY OF THE DOMESTIC FOWL

Summary of Bones Supplied by Each Air-sac.—The thoracic air-
sac communicates on each side of the thorax with twelve bones,
including the four sternal ribs. It supplies air to the clavicles, which
are perforated at both their extremities, and to the coracoids, which
are perforated just below their scapular extremity. The sternum
is supplied through two series of openings, the middle ones that
conduct air into the sternal ridge and the lateral ones, eight in
number and very small, correspond to the intercostal spaces. The
sternal ribs are penetrated by small foramina at their inferior ex-
tremities. From the subscapular extension the scapulz receive air
through one or two foramina at their anterior extremity. The
humeral prolongation supplies the humerus through a foramen
located at.the upper edge of the humeral fossa, at the infero-internal
part of the articular head.

The cervical air-sac furnishes air to all the cervical vertebra, to
all the dorsal vertebra, and to all the vertebral ribs. The anterior
parts of the vertebra of the neck are supplied with air through the
passage accommodating the vertebral artery. The posterior parts
of the vertebre are supplied by extensions from the interspinal
canal. The first extensions obtain entrance to the! anterior seg-
ments by one or more openings of the inner wall of the intertrans-
verse canals; the median extensions penetrate the posterior seg-
ments by two openings, a right and a left, situated on the inner wall
of those segments. The first dorsal vertebra is supplied with air
in the same manner, by the middle and the lateral canals of the
neck. This air, after passing through the first vertebra, leaves by
a lateral exit to enter a small air-sac. From this it passes into the
superior part of the second vertebra, escapes from this through its
lower portion, to be received into a lateral sac, and so on to the last
dorsal vertebra. These sacs also supply the vertebral ribs with
air, which enters them by very small openings located on their spinal
extremities.

The diaphragmatic air-sacs do not have communications with the
bones.

The abdominal air-sacs communicate with the sacrum, the
coccygeal vertebra, the iliac bones, and the femurs. The air
passing through the sacrum, the coccyx, and the ilium comes directly
from the supra-renal extensions; the air which fills the femoral cavity
comes from the femoral extensions.

In some birds these air spaces are more greatly developed than in

THE RESPIRATORY APPARATUS 205

others. The bones that are always aerated in all birds are the
cervical and the dorsal vertebre, the sternum, and the humeri.
Those aerated in some kinds only are the furculum, the scapule,
the vertebral and the sternal ribs, the sacrum, the coccyx, and the
femurs. Those that are never aerated are the bones of the forearm,
the hand, the leg, and the foot. ,

The service of air to the bones in most parts of the body by the
air-sacs, as just shown, is in special cases otherwise rendered. The
Eustachian tubes furnish air to the bones of the cranium and to the
upper jaw; while the lower jaw receives air from the pneumatic
foramen situated upon each ramus behind the tympanic articulation,
and from an air cell which surrounds the joint.

The cavities of the embryonic bones, which afterward become
pneumatic, are filled with marrow. Selenka states that the invasion
of the bones by the air is a late development, and that in the humerus
this invasion occurs after the twenty-second day in the life of the
chick.

Hunter and Compar, who have made extensive researches, con- .

sider the function of the air-sacs as threefold.

First, the air-sacs are subsidiary respiratory organs, which aid.

in ridding the blood of waste products and in taking in oxygen.

Second, they aid mechanically. the actions. of respiration in birds.
During the act of inspiration the sternum is depressed, the angle
between the vertebral and the sternal ribs is made less acute, and
the thoracic cavity proportionately enlarged; the air then rushes
into the lungs and into the thoracic receptacles, while those
of the abdomen become flaccid. When the sternum is raised, or
approximated toward the spine, part of the air is expelled from the
lungs and the thoracic air-sac through the trachea, and part is
driven into the abdominal receptacles, which are thus alternately
enlarged and diminished with the expansion and the contraction of
the thorax. Hence the lungs, notwithstanding their fixed condition,
are subject to due compression through the medium of the contigu-
ous air receptacles, and are affected equally and regularly by every
motion of the sternum and of the ribs.

Third, they reduce decidedly the specific gravity of the whole
body. This must necessarily follow from the large spaces filled with
air as well as from the absence in the bones of marrow and other
fluids. The air-sacs by their position also render equilibrium more
stable.

ANGIOLOGY

The Circulatory Apparatus.—The circulatory apparatus consists of
two tubular systems: the blood vascular system and the lymphatic
system. :

The blood vascular system consists of the heart, the arteries, the
veins, and the capillaries.

The heart is the central, propelling organ. The arteries form a
series of efferent tubules, which, by branching, constantly increase
in number and decrease in caliber, and which serve to carry the
blood from the heart to the tissues. The capillaries are extensions
from these latter tubules into which the arteries empty, and through
the walls of which the interchange of elements between the blood
and the other tissues takes place. The veins form a system of
converging tubules which receive the blood from the capillaries,
decrease in number and increase in size as they approach the heart,
and return the blood to that organ.

The lymphatic system consists of capillaries and veins alone.
Asin the blood system, the lymph capillaries collect the effete mate-
rial and pour it into the lymph veins, and these in turn, carry it to
the large blood veins adjacent to the heart.

Both these systems have one and the same continuous lining,
which consists of a single layer of endothelial cells. In the heart
this lining is called the endocardium, and in the vessels, the endo-
thelium. It forms a perfectly smooth surface.

THE HEART (Fig. 21, No. 7)

The heart of the domestic fowl is located in the median line of
the thoracic cavity. It is more anterior and mesial than in mam-
mals. Its axis is parallel with the axis of the trunk. The lungs
being confined to the dorsal part of the trunk, the lower part of
the heart is not surrounded by them, but extends backward, the
apex resting in the anterior part of the anterior median fissure of the
liver.

The heart has the form of an acute cone (Fig. 50, No. 1), the apex

of which is bluntly rounded.
206

ANGIOLOGY 207

The heart is surrounded by a sero-fibrous sac, the pericardium.
This sac adheres to the cervical air reservoirs anteriorly and to the
diaphragmatic septum posteriorly. It is composed of two mem-
branous layers: the parietal, external, dense, and fibrous; and the
visceral, internal, and serous. The pericardial sac has no direct
attachment to the heart, except at the upper extremity where it
surrounds the large vessels emerging from it. The serous layer is
reflected over the outer portion of the heart, where it is called the
epicardium. The function of the pericardium is to prevent friction
during the beating of the heart. It contains a small amount of
serous fluid for perfect lubrication. This fluid is called the liquor
pericardii.

Internally the heart has four cavities: two auricles and two
ventricles. The right ventricle is more crescent-shaped than in
solipedes, and in a manner envelops the left ventricle in front and to
the right, though it does not reach the point of the heart. The
right auricle is larger than the left. The auriculo-ventricular valve
is not tricuspid asin mammals. This valve instead of being formed
as usual by a membranous curtain, with margins retained by cords
fixed to the walls of the ventricles, is composed of a wide muscular
leaf, which appears to be a portion of the inner wall of the ventricle
detached from the interventricular septum. This septum is convex;
and the auriculo-ventricular orifice is an oblique slit situated between
it and the muscular valve in question; so that, when the heart wall
contracts at the systole, the valve is applied against this septum and
closes the passage. The bicuspid, or auriculo-ventricular valve of
the left side usually has two segments, though occasionally there
may be three. The fossa ovalis is a depression behind the posterior
semi-lunar valve in the septum of the heart. The membranous sep-
tum closing the foramen ovale is complete and strong but thin and
transparent. The right auricle receives the blood from the two
venze cave coming from the anterior extremity, and from the
posterior vena cava. These empty into a sinus. The left auricle
has two vessels, the pulmonary veins which bring blood to it from
the lungs.

Structure of the Heart.—The heart is lined by a serous membrane,
the endocardium, which is a continuation of the endothelium of the
blood-vessels. There are a few muscular pillars in the inner wall,
called the columne carne. To give the heart its pumping power,
it is made up of contractile tissue, a specialized kind of muscle

208 ANATOMY OF THE DOMESTIC FOWL

called heart muscle. It is involuntary-striated and occupies an
intermediate position, both morphologically and embryologically,
between smooth involuntary muscle and striated voluntary muscle
(Fig. 74, No. 4). It, like striated voluntary muscle, is both trans-
versely and longitudinally striated. Heart muscle cells are short,
thick cylinders, which are joined end to end to form long fibers. By
means of lateral branches the cells of one fiber anastomoses with
cells of adjacent fibers. Each cell of heart muscle contains one
centrally located nucleus. There is no distinct sarcolemma, but
the sarcoplasm is more dense near the surface of the cell, which
gives it the appearance of an enveloping cell wall. There is a
zone free from fibrille around the nucleus. The longitudinal
fibrille, which make up the cell, are held together by a cement-
like. substance.

The main mass of the heart wall, called myocardium, consists of
the specialized muscular tissue just described. The myocardium
differs in thickness in different parts of the heart wall. It is thickest
in the left ventricle and thinnest in the auricles. The left ventricle
forces the blood through the systemic circulation and hence must
be thicker to give it more power than is needed for the right ventricle,
which forces the blood only through the lungs. The auricles are
thinnest of all; for they receive the blood and pass it only to the
chambers below. The auricular-appendages at the base of the heart
in fowls are not so well marked as in mammals. The auricular
muscles consist of an outer coat common to both auricles, the fibers
of which are transverse and of an inner coat, independent for each
auricle, the fibers of which are longitudinal. Between the two
coats, occur bundles of muscle the fibers of which run in various
directions. The disposition of the muscle tissue of the ventricles
is much more complicated. It is composed of several layers of
fibers intricately interwoven.

The endocardium, covering the inner surface of the myocardium,
forms a serous lining of all the chambers of the heart. At the
arterial and venous openings it is continuous with and similar in
structure to the intima of the vessels. The endocardium consists
of two layers, an external layer closely attached to the myocardium
and consisting of mixed fibers, including those of elastic tissue and
smooth muscle cells; and an inner, single layer of endothelial cells,
spoken of above.

The heart is supplied with nutrient blood by the two coronary

ANGIOLOGY 209

arteries, which are given off from the common aorta just above the
semi-lunar valves.

A right, or anterior, and a left, or posterior, coronary from their
point of origin, turn in a ventral direction between the root of the
aorta and the pulmonary artery, the right going to the right coronary
groove and the left to the left coronary groove in the crown furrow.
From here they send branches into the heart. The anterior, right,
coronary, or coronaria dextra, the larger, is given off from the
inferior wall of the aorta. It divides into a ramus superficialis
and a ramus profundus. The ramus superficialis enters the crown
furrow and divides into two or three branches on the right heart
wall. ‘These branches extend to the apex of the heart. Twigs from.
this artery along its course extend into the muscular wall reaching
the posterior of the coronary groove where they anastomose with
those of the left coronary, the ramus profundus, and with other
branches from the same artery. The ramus profundus, larger than
the preceding, gives off fine branches into the walls of the aorta and
of the pulmonary artery, then enters from behind into the right wall
of the septum ventriculorum, extends into the apex of the heart, and
supplies the septum, or right inner chamber wall with the last branch,
this breaking through the posterior wall of the auricular appendage.

The posterior, Jeft coronary, or coronaria sinistra, originates from
the dorsal wall of the aorta, proceeds as one branch on the upper
surface of the left auricular appendix, and then extends between the
left appendix and the pulmonary artery to the ventral surface of the
heart. On the left side it supplies the wall of the pulmonary artery
and gives off a ramus profundus. It sometimes divides into two
parts and supplies the ventral wall of the right chamber and then
extends to the left wall of the septum medium. The rest of the
coronaria sinistra enters into the left crown furrow as the ramus
superficialis, which provides the left and dorsal upper surface of
the left chamber to the apex. From this furrow it extends into the
left chamber and the left appendage, and finally fuses with the
ramus superficialis of the coronaria dextra.

THE BLOOD-VESSELS

The blood-vessels consist of arteries, veins and capillaries.
The Structure of the Capillaries and Arteries.—The capillaries
are minute vessels which connect the arterioles, or terminal arteries,
4

210 ANATOMY OF THE DOMESTIC FOWL

with the venules, or terminal veins. They are only from 6 to 14
microns in diameter. Their walls consist of a single layer of
endothelial cells, which are somewhat elongated in the long axis
of the vessels. Their edges are serrated, and are united by a small
amount of intercellular cement-like substance. Capillaries branch
without diminution in caliber, and these branches anastomose to
form capillary networks, the meshes of which differ in size and shape
in different tissues and organs. The largest meshed networks occur
in the serous membranes and in the muscles; and the smallest occur
in the glands, such as the liver.

The walls of the arteries are thick and stand open when empty,
owing to the elastic tissue contained in their walls, while the walls
of the veins collapse when empty, owing to their containing a smaller
amount of elastic tissue. The arterial wall is provided with three
coats: tunica intima, or inner coat; tunica media, or median coat;.
and tunica adventitia, or outer coat. ?

The tunica intima consists of a single layer of endothelial cells,
continuous with and similar to that forming the walls of the capil-
laries. In passing from the capillaries to the arterioles, there is first
a thin coat, or sheath-like layer, of connective tissue around the
outside of the endothelial tubes. Further along, isolated smooth
muscle cells arranged in a circular manner occur between the endo-
thelial layer and the layer of connective tissue, this structure
forming vessels called precapillary arteries. Further along still,
the muscle cells form a complete layer; in this section the vessels
are called arterioles and are made up of three coats: the inner endo-
thelial, the middle muscular, and the outer fibrous.

In arteries of medium size the intima consists of the endothelial
layer, a layer of delicate white and elastic fibers, connective-tissue
cells, and the membrana elastica interna, or an outer layer, the
elastic layer, of the intima. .

The media consists of a thick coat of circularly arranged smooth
muscle cells, its thickness depending largely upon the size of the
vessels. There is also a small amount of fibrillary connective tissue,
which supports the muscle cells. Elastic tissue is present in the
media, the amount depending on the size of the vessel, the larger
the vessel the more elastic tissue there is present. In the large
arteries coarse elastic fibers intermingle with the finer ones. When
much elastic tissue is present the muscle cells are separated into
more or less: well-defined groups.

ANGIOLOGY 211

The adventitia is composed of loose connective tissue with some.

elastic fibers. A few smooth muscle cells are present, which, as are
also the elastic fibers, are arranged longitudinally. The adventitia,
blending with the connective tissue surrounding the arteries, serves
to anchor the vessels to the surrounding structure.

Structure of the Veins.—In many respects the walls of the veins
resemble those of the arteries. The same three coats exist and the
same elements enter into their structure. The transition from capil-
lary to small veins, and from those to larger veins, is similar to the
transition from the arteries to capillaries, in inverse order. The
walls are not so thick as those of arteries. The elastic tissue is
much less in-quantity and in smaller veins disappears. There is
not a clear line of demarcation between the intima and the media.

The veins of birds differ from those of mammals in that they have
fewer valves. The valves are also less perfect, and often permit a
backward flow of bfood.

.The walls of the arteries and of the veins are supplied with nutri-
ent blood-vessels. These are caJled the vasa vasorum, or blood-ves-
sels of the blood-vessel wall. They are mostly in the adventitia.
They may arise from the vessel to which they are distributed or take
origin from an adjacent vessel. These small arteries supplying the
vessel coat after terminating into capillaries form small veins through
which the blood, from the structure of the vessel wall, is returned.

The walls of the blood-vessels are supplied with both medullated
and non-medullated nerves. The non-medullated nerve fibers are
axones of the sympathetic neurones and control the caliber of the
vessels. These fibers are called the vasomotor nerves. They form
plexuses in the adventitia, from which are given off branches which
penetrate the media and terminate on the muscle cells. The medul-
lated nerves are the axones of the spinal nerves. The larger fibers
are found in the connective tissue outside the adventitia and give
off branches to the media where they divide repeatedly, lose their
sheath, and terminate in the media and at times in the intima.

THE ARTEFRIAL TRUNKS

The common aorta is short; it originates from the left ventricle
(Fig. 61B, No. K,14), and is guarded by three semi-lunar valves. The

aorta breaks through the pericardium just to the right of the pul.

monary arteries in a ventral] direction; it then turns upward dorsally
and to the right of the inferior bodies of the vertebre. It is then

a

212 ANATOMY OF THE DOMESTIC FOWL

directed anteriorly, and dorsally to the right bronchus, between the
right bronchus and the right lung. The right and the left coro-
naries are given off from the common aorta; they have been dis-
cussed. There is-next given off the left brachio-cephalic or brachto-
cephalic sinister artery (Fig. 61B, No. K, 10), which is just above the
border of the base of theheart. Thisartery passes upward and slightly

Fic. 61B.

K. The arterial trunks. 1, The middle sacral artery. 2, The hypogastric
artery. 3, The posterior mesenteric artery. 4, The ischiadic artery. 5, The
femoral artery. 6, The renal artery. 7, The left pectoral artery or thoracico
caudalis. 8, The left axillary artery. 9, The left carotid artery. 10, The left
brachio-cephalic artery. 11, The right carotid artery.. 12, The right brachial
artery. 13, The right pectoral artery. 14, The common carotid artery. 15,
The posterior aorta. 16, The celiac axis. 17, The anterior mesenteric artery.
18, The right brachio-cephalic artery. 19, The auricular portion of the heart.
20, The ventricular portion of same. 21, Sterno-clavicular artery. 22, Anterior
thoracic.

‘* L. The venous trunks. 1, The caudal vein. 2, The coccygeo-mesenteric
vein. 3, The posterior mesenteric vein. 4, The anterior mesenteric vein. 5,
The gastro-duodenal vein. 6, The portal vein. 7, The hepatic vein. 8, The
left anterior vena cava. 9, The left pectoral vein. 10, The left brachial vein.
11, The left jugular vein. 12, The right jugular vein. 13, The right brachial .
vein. 14, The right pectoral vein. 15, The right anterior vena cava. 16, The
posterior vena cava. 17, The common iliac vein. 18, The femoral vein. 10,
The renal vein. 20, The internal iliac vein. 21, The hypogastric vein. 22,
The auricular portion of the heart. 23, The ventricular portion of same.

forward, over the center of the inferior larynx. Just beyond this
point the subclavian artery is given off; this artery later becomes the
axillary and the axillary the brachial artery. Then there is given
off the anterior and the posterior thoracic arteries; and finally, the
pectoral, which supply the pectoralis muscles and latér terminate
in the carotid, the vertebral, and the cervical arteries. The carotid

ANGIOLOGY 213

artery gives off an esophageal artery. The other arterial trunk given
off from the common aorta is the right brachio-cephalic or brachio-
cephalic dexter (Fig. 61B, No. K, 18). The right brachio-cephalic
artery gives off the subclavian, which continues as the axillary,
and continues as the brachial artery. There is given off the anterior
and the posterior thoracic, the right carotid (Fig. 61B, No. K,11), the
vertebral, and the dorsal. The last continues as the cervical.

_ The pulmonary arterial trunk is given off from the conus arteriosus
of the right ventricle. It is guarded at its origin by three semi-lunar
valves similar to those of the aorta. The trunk divides into two
pulmonary arteries, which are short, one called the pulmonalis
dexter and the other the pulmonalis sinister. The former goes to

BRANCHES OF THE BRACHIO-CEPHALIC ARTERY

Thyroidea
Cervicalis inferior
Vertebralis anterior
Vertebralis posterior
| Arteria cervicalis ascendens
Bronchiales
(Truncus | Inferior esophageal
caroticus | Subcutaneous colli
Carotis cerebralis
Carotis Cervicalis superior
communis | Occipitalis
| Carotis externa
| Spinalis anterior { Basilaris { Cerebelli inferior

Vertebralis

Brachio-cephalic
. Clavicularis

( Sterno-clavicularis f Sternalis

| Acromialis

Subscapularis
Ulnaris
\Subclavia | Axillaris Brachialis | Brachialis profunda
Radialis
Humeralis | Circumflex humer-
| alis anterior
Thoracica externa

Arteria thor-
acica longa.

» Thoracahs Thoracica inferior [

Mammaria interna

Circumflex humeralis posterior
Brachialis profunda | Collateral ulnaris
( Collateral radialis

x

214 ANATOMY OF THE DOMESTIC FOWL

the right and the latter to the left lung. Each branch penetrates
the lung near the bronchus. These arteries divide, or branch,
similarly to the bronchi. Following the branchings of the bronchi,
they finally terminate into the lung capillaries, forming networks
on the bronchi and the air-tube terminals.

The cord-like remnant of the ductus botalli, or embryonal connec-
tion between the lung arterial trunk and the anterior aorta, has
been observed but is rare in grown birds.

The arteries, the veins, and the lymphatic vessels of birds anas-
tomose far more frequently than those of mammals.

BRANCHES OF THE ARTERIA CAROTIS CEREBRALIS INTERNA
Occipitalis: sublimis

Occipitalis profunda { Meningea
Temporalis

Oceipitalis (

: Rete temporale
Ophthalmica | Recurrent ophthal- Rete ethmoidalis
externa | micum | Ethmoidalis
: Plexus palpebralis
Plexus alveolaris inferior
Plexus muscularis
Carotis cerebralis | Plexus temporalis | Plexus lacrimalis
Ramus ciliaris posticus
| Meningea media

Sphenoidea Ethmodalis
Spheno-maxillaris Ethmoi- externa
Ophthal- | dalis Ethmoidal is
; mica in- | interna
Cere- terna

bralis | Ramus Sylvie

anterior | Cerebralis profunda { Choroid plexus
Arteria centralis retine
Ramus posterior

BRANCHES OF THE ARTERIA CAROTIS EXTERNA
Hyoidea

Laryngea superior

Facialis

Lingualis

BRANCHES OF THE ARTERIA CAROTIS FACIALIS
Auricularis

Facialis | Facialis interna { Alveolaris inferior {Mentalis

Maxillaris interna
Facialis externa

Carotis externa

ANGIOLOGY 215

BRANCHES OF THE CAROTID TRUNK

The carotis communis artery springs from the carotid trunk of
the brachio-cephalic. It is directed horizontally, ascending to the
ventral side of the neck. It then extends downward to the inferior
median neck region. Just after leaving its origin it gives off several
small branches to the bronchi and to the esophagus, and extends
toward the head. The carotid lies on the thyroid gland and at this
point, touches the jugular vein (Fig. 21): At this point the thyroid
arteries are given off from the carotid trunk. The thyroid gland
also receives blood from the bronchialis artery.

Dorsalward and near the thyroid gland the carotid artery gives
off a branch (the bronchialis) which accompanies the recurrent
laryngeal nerve, along the inferior larynx and the bronchi, and
supplies the lung substance and that part of the esophagus in this
region.

The vertebral artery is given off from the carotid trunk, dorsal-
ward to the thyroid gland, and on the left side. The right vertebral
artery may be given off from the brachialis dextra or right brachialis.

The inferior esophageal artery is given off from the ventral side
of the carotid, supplies the esophagus, extends then to the skin of
the neck and to the trachea, is directed anteriorly toward the
head and anastomoses with the vertebral artery. This artery ac-
companies the vagus nerve and forms a collateral artery to the
carotid and the-vertebral artery.

The subcutaneous colli springs from the carotid artery near
the thyroid gland and communicates with the inferior cervical artery,
which, in turn springs from the vertebral artery.

The Common Carotid.—Near the last cervical: vertebra the two
carotid arteries occupy the same channel, to which they are attached
by fascia, and, lying close to the inferior surface of the bodies of the
cervical vertebre, are covered by the colli muscles. Near the third
or the fourth cervical vertebra, the two carotid arteries separate.
Near the atlas each carotid divides into the carotis cerebralis and
carotis externa. Near this division the superior cervical artery
branches off. This latter artery extends down the neck in company
with the pneumogastric nerve and the jugular vein, supplies the
skin and the neck muscles, and anastomoses with the inferior cer-
vical artery and the subcutaneous colli artery.

216 ANATOMY OF THE DOMESTIC FOWL

The occipital artery originates either from the carotis communis

or sometimes from the superior cexvical. ante
BRANCHES OF THE Pilinral oa

The branches of the carotis cerebralis are as follows:

1. The occipitalis (Fig. 72, No. 18), which in turn gives off, first,
the occipitalis sublimis. The occtpitalis sublimis supplies the outer
and the middle portion of the digastricus and the posterior mylo-
hyoideus muscle. It also gives off, second, the occipitalis profunda
which supplies the inner portion of the digastricus muscle and
becomes the meningeal artery, which passes through the foramen
vagi, entering the brain cavity, where it supplies the coverings of
the brain as far as the sella turcica. Superficial branches of this
artery are distributed to the muscles in the region of the atlas and
anastomose with the vertebral artery.

2. The oph ica externa, which passes below the articulation
of the quadraté bone, around the tympanic cavity,.enters the
canalis caroticus, and passes into the cranial cavity. The ramus
occipitalis, passing out of the same foramen, again enters the diploé
of the cranium; then after passing dorsally over the upper outer
semicircular canal of the ear, passes backward through the occipital
bone. A

The ophthalmica externa (Fig. 72, No. 9) forms a main trunk and
gives off two branches: the temporal artery and the recurrent
ophthalmic. The recurrent ophthalmic gives off the rete temporalis,
rete ethmoidalis, a branch to the orbital gland, and finally anastomo-
ses with its own branches and with those of the internal ophthalmic
at the olfactory foramen and aids in forming the ethmoidal artery.
These arteries supply blood by giving off branches to the muscles
of the eye, sclerotic coat, iris, choroid coat, and the ciliary bodies.
It gives off another branch to Harder’s gland, and finally anastomo-
ses with the ethmoidalis.

3. The plexus temporalis, rete mirabile ophthalmicum, or won-
derful network (Fig. 72, No. 8), is formed between the second and
the third trunk of the trigeminus nerve and the rete ophthalmicum.

Inferior to this is the alveolar plexus, which plexus accompanies
the third branch of the trigeminus into the lower jaw. Two main
branches form this plexus, one coming from the carotis facialis,
which anastomoses with the alveolar artery.

ANGIOLOGY 217

The palpebral plexus lies between the trunks of the trigeminus,
and supplies mainly the lower eyelid.

The plexus muscularis extends to the fifth portion of the temporal
muscle. ;

The plexus lacrimalis forms on the posterior orbital wall on the
ramus ethmoidalis and supplies the lacrimal gland and the upper
eyelid. It anastomoses with branches from the facial artery.

The ramus ciliaris, posticus supplies the inferior rectus and the
external rectus muscle of the eyeball. It anastomoses with the
ophthalmica externa.

The median meningeal artery passes through the foramen occupied
by the second branch of the trigeminal nerve. Passing into the
cranial cavity, it supplies the dura mater. Before passing into this
foramen, small branches are given off, which supply the skin and the
temporal muscle; and some branches anastomose with the superior
cervical and the ethmoidal arteries.

4. The Cerebral Artery.—Each cerebral artery enters the cranial
cavity through the canalis caroticus located in the sphenoid bone,
passes forward medially from the cochlea, dorsally from the Eusta-
chian tube, and passes through a small canal which opens on the
inner surface of the sella turcica. Originating in this foramen, the
sphenoid artery divides into two branches which anastomose with
the pterygoidean and the pterygo-pharyngeal artery and which
supply the upper jaw and the throat regions.

The spheno-maxillaris artery supplies the gums.

The right and the left cerebral arteries unite at the sella turcica.
After this union they divide again immediately and pass to the
base of the brain, where they give off twigs to the optic nerve, to
the optic chiasm, and where also is given off the arteria retine
centralis. Passing posteriorly each cerebral artery gives off the
ramus posterior, and then passes to the side of the cerebellum.

The basilar artery, a continuation of the anterior spinal artery, is
located ventrally and mesially to the cerebellum. Laterally and
inferiorly the basilar artery gives off the inferior cerebellar artery.

The ramus anterior is given off from the cerebralis artery and
continues as the internal ophthalmic artery. The ramus anterior
also gives off the sylvian artery, which supplies the sides of the cere-
brum and the middle brain. In the fissure between the hemi-
spheres and the optic thalamus is located the arteria cerebri profunda.
This artery passes along the median surface of the cerebrum and in

218 ANATOMY OF THE DOMESTIC FOWL

its course supplies the adjacent parts. It enters into the formation
of the choroid plexus of the lateral ventricle.

The internal ophthalmic artery extends out of the cranial cavity,
through the optic foramen, into the orbital cavity. It passes
upward along the interorbital wall and. supplies the optic nerve,
the trigeminus nerve trunk, and the eye muscles, and dorsally
anastomoses near the olfactory nerve with the rete ethmoidale and
the external ophthalmic artery, and continues as the ethmoidal
artery.

The ethmoidal artery supplies the supra-orbital gland and the
gland of Harder. It gives off twigs to the rete ophthalmicum and
other branches to the skin of the frontal region, where it anastomoses
with branches of the external facial artery. These branches in
the frontal region are rather large. Large branches are given off
to the comb.

The arteria ethmoidalis externa originates in the nasal cavity from
a division of the ethmoidal artery.

The external ethmoidal artery passes below the lacrimal bone,
extends forward, supplies the walls of the nasal cavity, and finally
sends a branch anteriorly into the upper median ‘portion of the jaw
bone, and other branches to the septum nasi and other parts of the
nasal cavity. :

There are frequent anastomoses between the ethmoidalis interna,
the facialis, and the spheno-maxillary artery.

The internal ethmoidal artery supplies principally the posterior
turbinated bones and septum nasi.

a

BRANCHES OF THE EXTERNAL CAROTID ARTERY

Branches from the external carotid and the facial artery supply
the’ tongue and its muscles, the larynx, the lower jaw bone, the
gums, and the upper lateral facial region.

The external carotid (Fig. 62, No. A, 8) gives off the following
branches:

First, the hyoid artery (Fig. 72, No. 12) which supplies the inner
portion of the depressor mandibular and also the cornua of the
os hyoideum, and extends to the tip of the tongue.

Second, the superior laryngeal artery (Fig. 72, No. 16) which
supplies the sterno-brachialis and gives off branches which extend
downward to the trachea and to the esophagus. The main artery

ANGIOLOGY 210

oe

Fic. 62.

"A. Blood-vessels of the head. 1, The cerebellum. 2, The cerebrum. 3,
The semicircular canals. 4, Sinus occipitalis superior. 5, Sinus temporalis
sphendideus. 6, Sinus transversus dexter. 7, Superior esophageal artery. 8,
Carotis externus. 9, Lingual artery. 10, Sinus longitudinalis.

B. Veins of the antero-inferior part of the head and'neck. 1, The right carotid
artery. 2, The left carotid artery. 3, Vena jugularis dexter. 4, Vena verte-
bralis dexter. 5, Transverse vein. 6, Vena cephalica dexter anterior. 7, Vena
‘lingualis. 8, Vena cephalica posterior. 9, Vena facialis externa dexter. 10,
Vena infrapalatina. 11, Posterior nares. 12, Vena facialis interna. 13, Vena
facialis externa sinister. i

C. The brain. 1, Medulla oblongata. 2, Cerebellum. 3, Optic lobe. 4.
Cerebrum. 5, Longitudinal fissure. 6, Transverse fissure. 7, Olfactory nerve.
8, Optic nerve. 9, Optic commissure. 10, Motor oculi. 11, Patheticus. 12,
Trigeminal, or trifacialis. 13, Abducens. 14, Facialis. 15, Auditory, or acous-
ticus. 16, Glosso-pharyngeus. 17, Pneumogastric. 18,Spinalaccessory. 19,
Hypoglossus. 20, Hypophysis. 21, Crus cerebri. 22, Ganglion on superior
nerve trunk. 23, Spinal cord. 24, A pair of spinal nerves.

220 ANATOMY OF THE DOMESTIC FOWL

passes along the left side of the esophagus and anastomoses with
branches of the inferior esophageal, forming collateral circulation
in that region.

Third, the lingualis artery (Fig. 62, No. Ag) which lies between the
mylo-hyoideus and the posterior part of the hyoid bone. It sup-
plies the tongue muscles. It passes to the median surface of the
lower jaw bone, where are given off small branches which enter
the jaw and anastomose with the inferior alveolar artery.

Fourth, the Facial Artery—The facial artery divides into the
following branches:

The auricular artery is given off near the articulation of the os
quadratum with the os zygomaticum. It is locdted at the outer
auditory canal,'and its branches are distributed to the parotid
region and to the depressor mandibular, or digastricus, muscle.

The external facial artery is located between the os quadratum and
the masseter muscle. It gives off a branch to the lower jaw bone
and to the skin of that region, and then passes to the lacrimal bone
and supplies branches to the commissure of the mouth, the auditory
canal, the masseter muscle, the three eyelids (upper and lower eye-
lids and the membrana nictitans), the nose cavity, and the skin in
the frontal region. It communicates on the other side with the
ethmoidal artery.

The internal facial artery passes over and through the os ptery-
goideum, supplies all the jaw se and is continued as the inferior
alveolar artery.

The inferior alveolar artery enters the canal of the lower jaw bone
along with the mandibular nerve. It is finally continued as the
mental artery, leaving the canal, and passing to the outer jaw surface.

The facialis continues as the internal mavillary artery.

The internal maxillary artery (Fig. 72, No. 15) supplies the ptery-
goid muscle, the upper part of the pharynx, the commissure of the
mouth, the salivary gland region, the gums, and finally anastomoses
with branches of the spheno-maxillaris artery.

BRANCHES OF THE VERTEBRAL ARTERY

The vertebral artery is given off, dorsally near the thyroid gland,
from the carotis communis or from the carotid trunk. The verte-
bral artery passes horizontally and dorsally into the canals formed
in the transverse processes of the cervical vertebre. After it
leaves the carotid, it is divided into anterior and posterior branches.

ANGIOLOGY 221

The posterior vertebral artery passes in the canals of the trans-
verse processes of the fifth or sixth dorsal vertebra. It sends
branches into the vertebre, into the spinal canal, and into the
intercostal muscles between the ribs and anastomoses with the
intercostal arteries.

The anterior vertebral artery is larger than the posterior. It
extends laterally along the side of the neck in the foramen of. the
transverse processes of the cervical vertebre, and lies along the
course of the inferior vertebral vein and the deep imbedded trunk
of the sympathetic nerve. It continues to the head. In its passage
it gives off to each vertebral segment a dorsal and a ventral branch.
Twigs from these branches pass into the bodies of the vertebre and
the spinal canal, giving nutriment to the bony structure and to the
spinal cord and its coverings. Other twigs are distributed to the
muscles of the neck and some finally anastomose with branches of
the carotis communis. This artery, reaching the head, gives off a
long anastomosing branch which passes between the atlas and
posterior part of the occipital bone and joins the ramus profundus
and the occipital artery, thus again communicating with the carotid
artery. The remainder of the vertebral artery is small and passes
through the foramen magnum into the cranial cavity where it
anastomoses with terminal branches of the cerebral artery. At the
base of the neck and before the vertebral artery enters the canal of
the cervical vertebra, it gives off the arteria cervicalis ascendens,
superior artery of the crop (Fig. 73, No. 18) which branches out on’
the upper surface of the crop is a]so distributed to the neck muscles,
and later subdivides into the transverse cervical arteries which
supply the skin and the muscles of the base of the neck, and the
shoulder region.

On the ventral side of the neck there are given off two subvertebral
carotid arterial branches. They lie in a shallow furrow on the
ventral side of the cervical vertebra and close to the median line.

BRANCHES OF THE SUBCLAVIAN ARTERY

The subclavian artery (Fig. 20, No. 13; Fig. 73, No. 11) gives off
the following branches:

1. Sterno-clavicularis (Fig. 73, No. 9) which originates on the
upper part of the subclavia, between the carotid artery and external
thoracic (Fig. 73, No. 3), divides into many branches. The sterno-

222 ANATOMY OF THE DOMESTIC FOWL

clavicularis gives off the sternal artery, which enters by the side of the
supra-coracoid muscle and the anterior rim of the sternum. It is
distributed to the inner surface and over the air-sac. Another
outside branch passes the posterior end of the crista sterna and
supplies the large breast muscles.

The clavicular artery (Fig. 73, No. 8) accompanies the clavicle to
the shoulder-joint.

The acromial artery is given off from the sterno-clavicularis on
the Jigament near the shoulder-joint.

2. The thoracic artery branches from the subclavian artery (Fig.
70, No. 4). The thoracic artery gives off the following branches:

The internal mammary, or internal thoracic artery (Fig. 73, No. 16)
arises on the inner side of the sternum and extends downward and
backward, giving nutrient branches to the anterior vena cava and
to the diaphragm. At the point of the costo-sternal muscle it
divides into an inner and an outer branch.

The inner branch supplies the costo-sternal muscle and extends
along the ribs and along their juncture with the breast-bone. It
finally extends posteriorly, giving numerous branches to the abdom-
inal muscles. The outer branch is distributed in a similar manner,
giving off branches to the diaphragm and to the abdominal muscles,
and anastomoses, on the surface of the abdominal muscles, with the
epigastric artery.

The external thoracic artery (Fig. 73, No. 3), ramus superior,
supplies principally the large breast muscles.

The inferior thoracic artery, external ramus inferior, passes along
the outside of the pectoralis major muscle, extends downward,
and gives off the arteria thoracica longa (subcutaneous thoracic).
This latter artery supplies the skin of the breast region. Other
branches are given off to the muscles of the breast and to the skin
of the region, and some finally anastomose with the branches of the
sternal artery.

3. The axillary artery (Fig. 73, No. 12) extends out of the thoracic
cavity along with the brachial nerve plexus. It gives off the swb-
scapularis which supplies the muscles of the scapular region. The
axillary artery terminates as the brachialis which passes between
the biceps brachii and anconeus muscles downward along the
humeral shaft. It gives off the anterior humeral circumflex artery
and the brachialis profunda artery (Fig. 68, No. 3). It gives. off
near the elbow-joint the ulnar and radial arteries.

ANGIOLOGY 223

The anterior circumflex humeral artery passes through the short
head of the biceps and gives off a branch to the biceps muscle,
supplying the insertional part of the breast muscles.

BRANCHES OF THE BRACHIALIS PROFUNDA

The brachialis profunda artery (Fig. 68, No. 3) continues as the
posterior ‘circumflex humeral artery. This artery supplies the mus-
cles of the posterior part of the humerus, the skinof the wing, and
the muscles of the brachial region. The trunk of the arteria brachii
profunda passes downward along the anconeus muscle, supplying
that muscle and giving off the collateral ulnar artery. On the ulnar
olecranon it anastomoses with the recurrent ulnar, thus establishing,
at this region, collateral circulation. The rest of the brachialis
sends branches to the biceps muscle and to the skin of the upper
arm, and finally gives off the arteria collateralis radialis, which
supplies the condylo-ulnaris. It then anastomoses with the end
branches of the recurrent radialis artery.

The radial artery (Fig. 67, No. 4) passes downward on the outer
rim of the forearm. It continues down to the carpal region, where
it supplies the muscles and the skin of the carpal region it gives off
the recurrent radial, which passes on the middle finger and finally
anastomoses with the collateral radialis artery.

The ulnar artery (Fig. 68, No. 6 and 9) passes downward on the
inner surface of the ulna to the carpal region where it gives off a
branch to the wing plexus and divides into two branches, the smaller
branch supplying the thumb (Fig. 68, No. 7). This branch passes
down the radial side of the middle finger to the last joint of the
second finger. The larger (Fig. 68, No. 8) lies between the second
and the third finger bones, and passes through a slit between these
two bones to the flexor side of the hand and extends to the last
finger-joint, supplying the structures in the region. The ulnar
artery gives off a small arterial twig to the papilla of each large wing
feather (Fig. 67, No. 6).

The recurrent ulnar passes backward to the olecranon of the ulna
and supplies the muscles, the skin, the feathers, and other structures
of the region, and terminates in end collateral ulnar branches
(Fig. 67, No. 5).

224 ANATOMY OF THE DOMESTIC FOWL

BRANCHES OF THE POSTERIOR AORTA!

( Esophageal
Intercostales
Dorsal
Lumbars
Spermatics
Renals
Ovarian
Recurrent esophageal
Recurrent intestinalis { Recurrent ilio-colicus
Celiac | Posterior or recurrent sinister ( Renalis
axis | Anterior or recurrent dexter Splenics
Hepatic

Hepatica dextra ( Gace

{ Coccygee laterales

Saerghsanedia | Coccygea media ( Coccygez laterales

Posterior

aorta Recurrent ilio-celiacus
Recurrent superior hemorrhoidal
Posterior mesenteric {Median hemorrhoidal

Recurrent renalis

Tibialis postica:
| Tibialis antica { Peroneal [ Anterior tibial plexus
| Arteria ovarialis

Renalis
Hemorrhoidalis intima
Pudenda externa

Anterior mesenteric f
Ischiadica

Pudenda communis

Circumflex femoris
Femoralis .

Crural
(External iliac)

[Gr pelvic (umbilical)

The posterior aorta (Fig. 63, No. 2) passes backward along the
inferior part of the bodies of the dorsal and lumbo-sacral vertebre.
In the thoracic cavity it lies dorsal to the esophagus. It gives
branches (esophageal) only to the esophagus during its passage as far
as the seventh dorsal vertebra. Following this point there are given
of several pairs of arteries which divide into a superior and an infe-
rior branch. The superior branch extends upward and anastomoses
with branches of the vertebral artery and other twigs coming from
the intercostal arteries. These latter arteries given off are small
dorsal arteries. The inferior branches extend downward between
the ribs and supply the intercostal muscles. The intercostal arteries

1Nomenclature used by Bronn.

ANGIOLOGY 225

do not take their origin from the aorta in numerous and regular
branches as in mammals; they consist originally of but few vessels,
which are multiplied by anastomoses with each other and with
the arteries which come out of the spinal canal. An arterial plexus
is thus formed around the head of each rib, from which a vessel
is sent to each of the intercostal muscles and ribs and are continued

» fly

in ae,

“2G ,
a
Zw

Fic. 63.—The vascular system injected. 1, The heart. 2, The posterior
aorta. 3, The right brachiocephalic artery. 4, The left brachiocephalic artery.
5, The anterior mesenteric artery showing its many branches and anastomoses
mear and on the intestines. It is accompanied by branches of the mesenteric
vein. 6, The rectal branch of the posterior mesenteric artery. 7, The duodenal
loop and pancreas showing the pancreatic artery. 8, The anus. 9, The cloaca.
ro, The liver. 11, The lungs. 12, The right subclavian artery. 13, The right
carotid artery. 14, The right anterior. vena cava. 15, The subclavian vein.
16, The right jugular vein. 17, Thecarotidtrunk. 18, The posterior vena cava.

into the muscles upon the outside of the body and its integuments.
The anastomosis of the intercostal arteries round the ribs is similar
to the plexus, which is produced by the great sympathetic nerve in
the same location. The lumbar arteries are given off farther pos-
teriorly and along the lumbar region. The lumbar, like the dorsal
branches are given off in pairs. These arterial branches pass along
the thigh and the upper sacral vertebral region, and supply those

parts. Ventrally they are covered by the kidneys and pass into
15

1226 ANATOMY OF THE DOMESTIC FOWL

the abdominal muscles. The posterior aorta gives off the spermatic
arteries and the ovarian artery. In the male the former supply
the testes. The ovarian artery of the female gives off a twig to each
calyx containing an ovum. Each calyx is voluminously supplied
with blood. Next the renal arteries are given off to the kidneys.

;
7

Fic. 64.—The splanchnic arteries, veins and nerves. 1, A portion of the left
testes. 2, Adrenal gland. 3, Anterior lobe of kidney. 4, Heart. 5, Liver.
6, Second portion of the esophagus. 7, Proventriculus. 8, Gizzard. 9, Spleen.
10, Duodenal loop. r1, Pancreas. 12, Blind extremity of cecum. 13, Float-
ing portion of small intestine. 14, Rectum. 15, Cloaca. 16, Anus. 17,
Celiac axis. 18, Ureter. 19, Vasdeferens. 20, Recurrent sinister artery. 21,
Anterior recurrent dexter artery. 22, Arteria hepatica dextra. 23, Recurrent
esophageal artery. 24, Recurrent intestinalis artery. 25, Ilio-colicus artery.
26, Anterior mesenteric artery. 27, Recurrent branches of the same. 28, Ilio-
ceeliacus artery. 29, Recurrent superior hemorrhoidal artery. 30, Posterior
mesenteric artery. 31, Crural arteries. 32, Sacralis media artery. 33, Recur-
rent renalis. 34, Middle renal lobe. 35, Posterior renallobe. 36, Vena mesen-
tericus communis. 37, Vena hemorrhoidalis. 38, Vena pancreatico-duodenalis.
39, Vena proventriculo-leinealis. 40, Vena portalis dextra. 41, Ischiadic nerve.
42, Thoracic sympathetic trunk. 43, Anter’or splanchnic plexus. 44, Spinal
nerves. 45, Posterior splanchnic nerve plexus. 46, Intestinal nerve trunk.
47, Vena renalis magna.

The celiac axis (Fig. 64, No. 17) originates near the seventh ster-
nal vertebra and to the right of the esophagus, breaks through the
diaphragm, and, near this point, gives off a recurrent esophageal
(Fig. 64, No. 23). The celiac axis gives off three main branches:
The anterior or recurrent dexter, the posterior or recurrent sinister,

ANGIOLOGY 227

the recurrent intestinalis, all of which lie to the right of the spleen,
under the left lobe of the liver, and along the left side of the stomach.
The recurrent sinister (Fig. 64, No. 20) gives arterial branches to
the proventriculus, the gizzard, the pyloris, and the left lobe of the
liver. The anterior or recurrent dexter (Fig. 64, No. 21) gives off a
renal artery and from four to six splenic arteries.

The recurrent intestinalis artery (Fig. 64, No. 24) arises on the
posterior of the stomach within the duodenal loop, and supplies
the duodenum and the pancreas (Fig. 63, No. 7). It gives off a
branch, called the recurrent ilio-colicus (Fig. 64, No. 25), which
supplies the large intestines, including the czca.

The arteria hepatica dextra (Fig. 64, No. 22) is a branch from the
celiac axial trunk. It gives several branches to the right lobe of
the liver and to the gall-bladder. The gastric branches pass to,
the muscles of the stomach. The anterior and posterior recurrent!
branches often anastomose.

The anterior mesenteric artery (Fig. 63, No. 5; Fig. 64, No. 36)
originates from the posterior aorta near the generative glands. It.
is directed downward, and divides into many branches which pass:
in the mesentery toward the intestines. Recurrent branches (Fig..
64, No. 27) are given off, which anastomose, forming mesenteric
arches., From these arches are given off branches which supply the
intestinal walls.

The anterior mesenteric artery gives off the recurrent ilio-celiacus
(Fig. 64, No. 28) which is distributed to the ceca; other of its
branches are distributed to the small intestine.

The anterior mesenteric artery extends along the small intestiné
and ends in the recurrent superior hemorrhoidal arteries (Fig. 64; No.
29) which anastomoses on the surface of the rectum with a branch
of the posterior mesenteric artery.

Branches from the anterior mesenteric artery also anastomose
with branches of the celiac axis.

The posterior mesenteric artery (Fig. 64, No. 30) is given off from
the posterior aorta posterior to the origin of the anterior mesenteric
and near the arteries of the thigh and is distributed to the lesser
mesentery supplying the large intestine. Branches of the superior
hemorrhoidal arteries anastomose with branches of the posterior
mesenteric artery. Branches from this source are called the median
hemorrhoidal (Fig. 63, No. 6).

The posterior mesenteric artery (Fig. 64, No. 30) also gives off a

228 ANATOMY OF THE DOMESTIC FOWL

long branch to the ceca. Branches of the posterior mesenteric.
artery anastomose with branches of the anterior mesenteric.

The crural arteries (Fig. 64, No. 31) are given off in a pair from
the posterior aorta. They pass through the mass of the lobes of the
kidneys, at about the median region, and extend out of the pelvic
cavity in front of, the spine and ilio-pubic ligament.

The crural, or the external iliac artery, is divided into three
branches as follows:

First, the internal pelvic, or umbilical artery, is given off just as.
the cruralis leaves the pelvic cavity. It passes, as a long vessel,
on the inner surface of the lumbo-sacral bones and supplies the

Fic. 65.—Blood-vessels and nerves of the hind extremity. Inside view of leg.
I, Ischiadic nerve. z, Ischiadic artery. 3, Posterior tibial vein. 4, Vena
metatarsa dorsalis interna. 5, Vena metatarsalis plantaris profunda. 6, Vena
cruralis. 7, Vena metatarsalis interna, vena magna.. 8, Vena tibialis postica.
9, Vena metatarsa magna. 10, Nerves of the toes. 11, Vena metatarsalis
dorsalis profunda.

obturator internus muscle and extends into the umbilical region.
It gives off branches to the abdominal muscles, and, in the female, a
branch is distributed to the ligament of the oviduct.

Second,. the erteria circumilex femoris, which passes between the
sartorius and vastus internus and extends dorsalward, supplies
the sartorius muscle, the vasti muscles, and the ilio-trochanteric
region.

- Third, the femoral artery, which passes beside the vena cruralis
and extends down the posterior surface of the thigh to the knee-
joint, supplies the upper thigh muscles with the exception of the
adductor muscles.

ANGIOLOGY 229

The ischiadic artery (Fig. 69, No. 9) forms the main artery of the
posterior extremity. This artery, the largest vessel of that region,
is given off from the posterior aorta and passes ventrally over and

Fic. 66.—Blood-vessels and nerves of the posterior extremity. Outside view.
1, Anterior tibial artery. 2, Metatarsalartery. 3, Digitalarteries. 4, Vena
cutaneous crurus. 5, Ischiadic artery. 6, Venacruralis. 7, Lateral cutaneous
branch of the ischiadic nerve.

between two of the main lobes of the kidney. The continuation
of the posterior aorta is called the sacralis media’ (Fig. 64,
No. 32). The ischiadic artery gives off a recurrent renalis on the

Fic. 67.—Blood-vessels and nerves of the fore limb. Outside view. I,
Median nerve. 3, Ulnarnerve. 4, Radial artery. 5, Recurrent ulnaris artery.
6, Twigs of ulnar artery to wing feathers.

posterior lobe of the kidney (Fig. 64, No. 33). On the left side it
gives off a branch to the oviduct and to the ligament of the oviduct.
The main trunk leaves the cavity with the ischiadic nerve (Fig. 65,

230 ANATOMY OF THE DOMESTIC FOWL

No. 1) through a foramen formed by the os ilium and the os ischium.
It sends branches into the.adductor muscles of the upper and the
lower thigh. It gives off anastomotic branches which unite with
those from the femoral artery. At the flexure of the knee-joint it
gives off two branches to that region (Fig. 69, No. 10). It gives off
another branch to the gastrocnemius muscle and one to the flexor
perforans digitorum. It terminates in the anterior and posterior
tibial arteries.

The first, the ébialis postica (Fig. 69, No. 12) passes
between the gastrocnemius and the deep flexors giving off branches

Fic. 68.—Blood-vessels and nerves of the fore limb. Inside view. 1, Vena
humeri profunda. 2, Brachialis longus inferior. 3, Brachialis profunda. 4,
Radial artery. 6, Ulnar artery. 7, Ulnar arterial branch tothumb. 8, Digital

. branch of ulnar artery. 9, Ulnar artery.

in its course to the skin and to other parts, and disappears shortly
below the intertarsal joint.

The second, the fibialis antica (Fig. 66, No. 1; Fig. 69, No. 11),
is often the larger of the two arteries. The anterior tibial artery
gives off branches to the knee-joint and to adjacent structures. It
gives a large branch to the head of the gastrocnemius muscle. It
passes to the posterior surface of the tibial head and gives off the
peroneal artery, which passes through the membrana interossea
located between the tibia and fibula giving branches to the anterior
side of the membrane of the patellar region of the knee-joint. It
gives branches to the anterior side of the lower thigh and finally
terminates subcutaneously in the anterior tibial plexus.

The main portion of the anterior tibial artery passes downward

ANGIOLOGY 231

along the posterior surface of the membrane located between the
tibia and fibula, and sends branches for the flexor digitorum com-
munis et profundus. It then breaks through the membrane,
reaches the anterior side and there communicates with the anterior
tibial plexus. It gives off branches to the muscles on the anterior
side of the lower thigh and the skin, and passes between the outer
and the middle malleolus of the tarsal bones. It passes to the
plantar surface and divides between the toes. In addition to the

Fic. 69.—Blood-vessels and nerves of the femoro-tibial region. A section of

the tibia removed.

A. Veins, arteries and nerves dissected as in B.

B. V, Vein. A,Artery. N, Nerve. 1, Venapoplitealis. 2, The three veins
forming the vena poplitealis. 3, Venafemorisinterna profunda. 4, Venafemoris
anterior. 5, Vena cruralis. 6, Vena cutanea abdominalis femoralis. 7, Vena
cutaneous cruralis. 8, Deep vein of the knee-joint. 9, Ischiadic artery. 10,
Branches of ischiadic artery to flexure of knee. 11, Anterior tibial artery. 12,
Posterior tibial artery. 13, Ischiadic nerve. 14, Trunk (a branch of the ischi-
adic) which gives off the superficialis peroneus and peroneus profundus. 15,
Median branch of ischiadic nerve. 16, Superficialis peroneus. 17, Lateral
branch of the ischiadic nerve.

plantar branches there are given off dorsal branches between the
third and the fourth toes. These branches form the direct continua-
tion of the dorsal vessels of the anterior tibial plexus.

The arteria pudenda communis (Fig. 70, No. 20) passes to the
depressor coccygeus muscle, gives off a branch to the caudal part
of the kidney, crosses the ureter, provides the ischio-pubic and
pubio-coccygeus, or depressor coccygis lateralis, muscles, and on

3

232 ANATOMY OF THE DOMESTIC FOWL

the lateral rim of the latter muscle it gives off the arteria hemorrhoid-
alis intima. This artery passes to the bursa of Fabricius and to the
end of the cloaca. It enters into the ischio-coccygeus muscle, and
divides into the arteria pudenda externa, and in ducks, the arteria
profunda penis. These branches supply the vas deferens, the ureter,
the cloaca, the penile structure, and the muscles of these parts.

Fic. 70.—Blood-vessels of a Cornish cock 1, The left pulmonary artery.
2, Right pulmonary artery. 3, Left brachio-cephalic artery. 4, Left subclavian
artery. 5, Left carotid artery. 6, Right brachio-cephalic artery. 7, Posterior
aorta. 8, Posterior vena cava. 9, Left pulmonary vein. 10, Right pulmonary
vein. 11, Celiac axis. 12, Anterior mesenteric artery. 13, Ischiadic artery.
14, Crop. 15, Superior artery of the crop and vein of samename. 16, Testicular
or ovarian artery. 17, Externaliliac artery. 18,Intercostalnerve. 19, Median
sacral artery. 20, Arteria pudenda communis. 21, Anus. 22, Vena hypo-
gastrica, 23, Right vena hepatica magna. 24, Left vena hepatica magna. 25,
Vena iliaca interna. 26, Vena iliaca communis. 27, Vena iliaca externa. 28,
Vena coccygo-mesenterica. 29, Vena umbilicalis. 30, Vena supra-renalis. 31,
Origin of the pars renalis. 32, Lumbar veins. 33, Vena epigastrica. 34,
Lumbales (arteries). 35, Anterior division of the lumbo-sacral plexus. 36,
Posterior division of the lumbo-sacral plexus. 37, Left anterior vena cava.
38, Right anterior vena cava.

The Sacralis Media.—The median coccygeal artery (Fig. °70,
No. 19) forms the single extension of the sacralis media. It gives
off lateral branches between the caudal vertebre which supply the
dorsal muscles of that region and the skin. The third pair are the
largest. These are the arterie@ coccyge@ laterales, and are located
on the dorsal side of the tail, they supply the tail glands and
rudder feathers, the main tail feathers, or rectrices. A small
arterial twig is given off to the papilla of each rectrix.

ANGIOLOGY 233

THE VENOUS TRUNKS

The venous blood enters the lungs from the right ventricle through

the two pulmonary arteries (Fig. 70, No. 1 and 2).
-The two pulmonary veins (Fig. 70, No. 9 and 10) collect the ar-

terial blood from the lungs, and empty it into the left auricle.

There are three vene cave which collect the systemic blood and
empty it into the right auricle. These vene cave are two anterior
(Fig. 70, No. 37 and 38) and one posterior (Fig. 70, No. 8).

Each anterior vena cava is formed by the union of a vena jugu-
laris, a vena vertebralis, and a vena subclavicularis (Fig. 63, No. 15).

Fic. 71.—Veins of the liver of a fowl. .1, Wena mesenterica communis.
2, Vena portalis propria. 3, Anterior vena mesentericus. 4, Vena portalis dex-
ter. 5, Vena portalis sinister. 6, Posterior venacava. 7, Celiac axis. 8, Base
of the heart. 9, The liver. 10, Hepatic veins.

The jugular vein is formed by the union of the vena cephalica
anterior, and the vena cephalica posterior.
_ The jugular vein (Fig. 62, No. B 3) passes along the side of the neck
and lies near the trachea, the esophagus, and the pneumogastric
nerve. Near the base of the skull the two jugular veins, the right
and the left, are connected by a transverse vein. By this anasto-
mosis part of the blood from the left jugular vein is sent into the
right. Therefore the right jugular vein is larger than the left. The
jugular veins collect the blood from the tongue region, the thyroid,
the esophagus, the trachea, the crop, and other structures along its
course through the cervical region.

*

J

234 ANATOMY OF THE DOMESTIC FOWL

Thevertebral veins are divided into the anterior and the posterior,
or the inferior and the superior. The anterior vertebral vein is located
in the cervical region and collects the blood from the brain and the
inner part of the head. The vertebral vein passes along the dorsal
side of the spinal cord.

BRANCHES OF THE VEN CAVE ANTERIORES

( Venz linguales

Vena occipitalis lateralis { Vena occipito-collores

Vena ascendenes lateralis

Venz-colli cutinee

Venez esophagealez

Venez tracheales

Vena Vena subscapularis
jugularis Venz glandularum thyroidearum

Vena occipitalis fore foraminis

interna occipitalis

Vena in-.
tercos-
tales

Vena
Vena cava vertebralis
anterior l

Vena vertebralis posterior
Vena vertebralis anterior

( Vena vertebralis
Vena vertebralis lateralis dorsalis \ Vena intercostales .

Venz coronarie
Vena subclavicularis
| Vena thoracica interna (Vena intércostales

Vena pharyngea superior
Vena muscularis depressoris mandibularis
Vena myscularis colli anterior superioris

| Vena lingualis

( Vena sublingualis et sphenoidea

Vena facialis
communis

The posterior vertebral vein is located in the dorsal region, passes
backward and receives the blood from the dorsal neck region and
from the intercostal veins and from the vertebral segments and
adjacent regions.

The anterior and the posterior vertebral vein form one trunk,
the vertebral vein, and this trunk empties into the vena jugularis
just before the subclavian and the jugular unite. ;

The subclavian vein collects the blood from the anterior extremi-
ties. It unites with the vena jugularis of the same side.

The left vena cava receives the coronary veins from the heart.

ANGIOLOGY 235

THE VEINS OF THE HEAD

BRANCHES OF THE VENA FACIALIS INTERNA

The vena facialis interna (Fig. 62, No. 12) lies dorsal on the ptery-
goid bone and receives the vena maxillaris, the vena ophthalmica, the
vena mandibularis interna, the vene pharyngez superiores, and the
vena retis mirabilis temporale.

Fic. 72.—Blood-vessels and nerves of the abdominal cavity and hind extremity
and head. 1, Vena renalis. 2, Vena intervertebrales sacrales. 3, Posterior
aorta. 4, External iliac. 6, Ischiadic nerve. 7, Ischiadic artery. 8, Arterial
rete (plexus temporalis). 9, Ophthalmic artery. 10, Palatine artery. 11,
Lingual artery. 12, Hyoid artery. 13,14, External carotid artery. 15, Inttr-
nal maxillary artery. 16, Superior laryngeal artery. 17, Superior esophageal
artery. 18, Occipital artery. 19, Internal carotid artery.

The vena maxillaris comes out of the upper beak with the re-
current trigeminus nerve and then passes backward between the
jugular and palatine bones. It lies medio-ventrally to the eye-
ball and communicates at this point with the ophthalmic vein. It
is covered ventrally with the pterygoid bone. The maxillary vein
collects the blood from the gland of Harder, the upper beak, and

236 ANATOMY OF THE DOMESTIC FOWL

receives blood from the vena supra-palatina and from the lower
jaw bone and the external mandibular vein. It also receives blood
from the external sublingual vein, and the sublingual gland. It
follows the inner rim of the jaw bone. The maxillary vein receives
an anastomosing branch from the cutaneous facial vein, at a point
near the commissure of the mouth. aos ;

Fic. 73.—Photograph of blood-vessels and nerves of the thorax. 1, Vena *
sternalis. 2, Venathoracico-externa. 3, External thoracic artery. 4, Coracoid
bone. 5, Sternum. 6, Shoulder-joint.’ 7, Humerus. 8, Clavicularis artery.
9, Sterno-clavicularis artery. 10, Thoracico-humeralis artery. 11, Subclavian
artery. 12, Axilla: . 13, Brachialis profundus artery. 14, nar
artery. 15, Radial artery. 16, Internal-mammary artery. 17, Superior vein
of the crop. 18, Superior artery of the crop. 19, Brachial nerve plexus. 20,
Anterior division of brachial nerve plexus. 21, Posterior division of brachial

nerve plexus.

The vena ophthalmica lies close to the point where the olfactory
nerve passes out of the cranial cavity. The largest branch it re-
ceives is the recurrent ophthalmo-temporalis, which accompanies the
lateval side of the optic nerve. It collects the blood from the base
of the brain, from Harder’s gland, from the eye muscles, from the

ANGIOLOGY 237

inner eye, the nose, the lacrimal gland, the skin of the frontal region,
and the comb. ”

BRANCHES OF THE VENA JUGULARIS

Vena maxillaris
; Vena ophthalmica
Vena facialis | Vena mandibularis interna
interna Vena retis mirabilis temporalis
Vena cephalica \ Venez pharyngee superiores
anterior or
facialis ( Vena facialis cutinea -
communis Vena temporalis
Vena facialis | Vena auricularis
Vena jugularis externa Vena palpebralis
or cephalica Vena transversus
communis Vena retis mirabilis temporalis

Vena subclavia

Venez vertebrales

Sinus cranii et cerebri
Vena carotis

Sinus fovee cerebelli
Vena occipitalis externa
Vena cephalica | Vena jugularis prima
posterior ena occipitalis
Vena lingualis
( Vena mandibularis externa
Vena maxillaris | Vena sublingualis externa
ent supra-palatina

Vena auris

Vena ophthalmica ( Vena ophthalmo-temporalis, recurrent
Vena facialis communis { Vena cephalica externa

Vena occipitalis externa {Vena occipitalis interna

Vena retis. mirabilis temporalis (Vena spheno-temporalis

Sinus fovez cerebelli { Sinus occipitalis externa

The trunk of the internal facial vein receives the blood of the
internal mandibular vein. The internal mandibular vein emerges
from the alveolar canal of the inferior jaw bone and receives branches
from the muscles of mastication.

The vena retis mirabilis temporalis passes out of the eye cavity
and lies between the internal facial vein: and the external facial
vein, and passes around the os quadratum and the os pterygoideum.
It receives veins from the outer ear region, lacrimal gland, eyelids,
and the spheno-temporalis.

238 ANATOMY OF THE DOMESTIC FOWL

The vene pharyngeze superiores are the veins on the dorsal
surface of the pharynx. These veins form the small plexuses which
unite with the two trunks of the facial veins. This forms an anas-
tomosis between the left and the right facial veins.

BRANCHES OF THE EXTERNAL FAcIAL VEIN

The vena facialis externa (Fig. 62, No. B, 9) lies behind the quad-
rate bone and is partly covered ventrally by the inner extension
of the lower jaw bone. It collects the blood principally from the
upper region of the cranium and the face, including the comb.

The vena facialis cutinea receives branches from the muscles in
the region of the jaw, the lower jaw bone, the muscles of the eyelids,
the frontal region, and the anastomotic branches from the vena
mazxillaris.

The vena temporalis is made up of veins from the skin of the tem-
poral region, the masseter and the tongue muscles, and from the
sides of the upper throat region.

The vena palpebralis is made up from veins from the three eye-
lids and the temporal region near the eye. Its trunk passes lat-
erally over the temporo-mandibularis ligament. The vena pal-
pebralis collects blood from the lacrimal gland, the eyelids, and the
outer ear region.

The following veins empty into the trunk of the vena facialis
communis: vene pharyngis superiores, vena muscularis depressoris
mandibule, vena muscularis colli anterior superioris, vena lin-
gualis et hyoidea. The right terminal branches of the vena lin-
gualis empty into the vena cephalica posterior. .

The vene pharyngis superiores and vena lingualis et hyoidea
collect blood from the muscles of the tongue and posterior tongue
region.

The vena lingualis et hyoidea (Fig. 62, No. B, 7) collects the blood
from the muscles of the tongue region, the lower tongue glands, and
the upper throat region.

Between the two trunks of the vena facialis communis and anterior
to the entrance of the vena cephalica posterior there is an anastomosis,
the vena transversus (Fig. 62, No. B, 5). Through this anastomosis
which lies crosswise the two jugular veins are influenced in different
ways. At this point both jugular veins are of the same size. The
anastomotic branch lies crosswise. Through this anastomosis the

ANGIOLOGY 230

right receives some blood from the left head region indicating that
the blood flows from left to right. This, as stated before, makes the
left jugular vein the smaller.

BRANCHES OF THE VENA CEPHALICA POSTERIOR

The left vena cephalica posterior (Fig. 62, No. B, 8) communicates
with the transverse vein (Fig. 62, No. B, 5). The left receives the
smaller veins of the skin region, the esophagus, and the trachea.
These vessels communicate with their fellow of the opposite side
and with the vertebral vein of the same side, which causes a gradual
reduction of the size of the jugular vein.

‘ BRANCHES OF THE VENA OCCIPITALIS EXTERNUS

Venez choroidee

Sinus Venez cutanez et frontales
longitudinalis | Venz nasales
Vena Venez ophthalmiz
occipitalis
externus ( Sinus occipitalis
Sinus ( Sinus Sinus temporo-sphenoideus
semicircularis | transversus | Venz cerebellares
Sinus petrosus sphenoideus
Sinus petrosus sphenoideus { Retis mirabile temporalis
Sinus temporo-sphenoideus ( Sinus annularis venosus basilaris
Sinus foraminus occipitalis { Venz medullares
Venez cerebrales
Sinus Vena cerebralis basilaris ( Sinus venosus annularis anterior
venosus |
annularis |
“basilaris Vena ophthalmica

| Vena medullaris mediana longitudinalis

The vena cephalica posterior (Fig. 62, No. B, 8) is formed from
the veins of the sinuses of the cranium, the brain, the vena auris,
the vena jugularis prima, the vena carotis, and the vena occipitalis.
It collects most of the blood from the cranium and the posterior part
of the head and from the tongue.

THE VENOUS SINUSES OF THE HEAD

The sinus longitudinalis (Fig. 62, A, 10) extends from the dorsal
median line of the internal occipital protuberance to the olfactory

240 ANATOMY OF THE DOMESTIC FOWL

nerve. It collects the blood from the choroidea of the brain and
from the skin of the frontal region. It receives laterally the veins
of the nose, the vena ophthalmica, and the sinus transversus.

The sinus occipitalis (Fig. 62, No. A, 4) forms the continuation
of the transverse sinus. It is located in the posterior cerebral
cavity, and is wing-shaped, extending both to the right and to the’
left.

The sinus foraminis occipitalis a continuation of the sinus occip-
italis, lies transversely on the ventral side of the cranial cavity
and rece ves the veins from the medulla oblongata. One branch
passes through thé os occipitalis basilare, and then .extends side-
wise to the foramen magnum and anastomoses with the vena
occipitalis.

The sinus transversus (Fig. 62, No. A, 6) extends in a pair from
the internal occipital protuberance between the cerebrum, cere-
bellum, and the corpus quadrigeminum. It receives vessels from
the upper surface of the cerebellum. The sinus has three branches,
all of which empty into the sinus semicircularis.

The sinus semicircularis extends along the dorsal petrosal rim,
anterior to the inner ear, and from this point backward. Near the
foramen magnum it passes through the os occipitale and. empties
into the external occipital vein.

The vena occipitalis externus extends near the foramen magnum,
surrounds the basis occipitalis, and receives the semicircular sinus
and thorugh the semicircular sinus the blood from the sinus trans-
versus.

The sinus petrosus sphenoideus, passing in company with the
occipital sinus, extends from the transverse sinus to the cavity near
which the trigeminus lies. The sinus dividing into two branches,
one of these extends to the hypophysis and unites with the basal
veins of the brain; the other passes with the rete out of the cranial
cavity along with a branch of the trigeminus, and communicates
with the rete mirabile temporale.

The sinus temporo-sphenoideus (Fig. 62, No. A, 5) extends for-
ward and outward from the transverse sinus, and, between the
corpus quadrigeminum and the cerebrum, unites with the sinus
venosus annularis basilaris.

The sinus venosus annularis basilaris lies in the region of the
optic nerve and surrounds the hypophysis, forming a complete circle.
It receives small vessels from the cerebrum, the corpora quadri-

ANGIOLOGY 241

‘'gemina, and anteriorly the longitudinal basilar vein or vena basilaris
media, of the cerebrum, which comes out of the anterior annular
venous sinus. The anterior annular venous sinus surrounds the base
of the olfactory nerves. It communicates with the sinus petrosus
sphenoideus, which emerges from behind the optic lobe, the sinus
temporo-sphenoideus, which emerges from in front of the optic lobe,
and posteriorly the median longitudinal vein of the medulla ob-
longata or vena basilaris. Laterally and anterior to the optic lobe
it receives the vena basilaris lateralis, and also a branch of the
vena ophthalmica.

The blood received by the sinus annularis basilaris comes from
the brain cavity through three pairs of veins, as follows: first, the
two ophthalmic veins which pass through the posterior orbital wall
between the olfactory and the optic nerve; second, two other bran-
ches of the ophthalmica which pass with the optic nerve; third, two
veins which pass through a foramen by the side of the sella turcica
to the hypophysis together with the carotis cerebralis, and then
leave the cerebral cavity ventrally, at which point they are called
the ven carotes. These last accompany the cerebral artery back-
ward, and pass through a foramen in the base of the cranium.
Each one then passes through the cranial wall close to the external
auditory canal, and empties into another vein in the posterior re-
gion of the head.

The sinus fove hemispherii cerebelli lies in the hollow between
the os petrosum and-the semicircular canals. It receives blood from
the external occipital sinus and from the cerebellum, and empties
into the vena auris interna.

VEINS OF THE BRAIN CAVITY

The vena auris interna passes through a bony canal along the
outer rim of the posterior semicircular canal and then along the
external semicircular canal. It receives vessels from the labyrinth,
and extends along the posterior rim of the tympanum to the outer
ear canal.

The vena occipitalis interna, extending from the sinus foraminis
occipitalis, passes through the side of the atlas and divides near the
condyle into two branches. One of these branches the internal
occipital, forms the root of the vena vertebralis, and the other

empties into the vena occipitalis externa.
16

242 ANATOMY OF THE DOMESTIC FOWL

Near the outer and upper part of the condyle it forms two large
veins and collects the blood from the vena occipitalis media. These
veins collect the blood from the rectus capitis anticus, and communi-
cate with the vena cephalica anterior.

The vena occipitalis externa, sometimes called the vena occip-
italis collateralis, extends from the vena auris, and receives vessels
from the neck region. It receives on the side of the occipito-
atloid joint the vena occipitalis interna. The vena occipitalis
externa forms a junction with the vena vertebralis emptying
into the transverse vein.

THE VEINS OF THE NECK
BRANCHES OF THE VENA JUGULARIS

The trunks of the vena jugularis or vena cephalica communis
pass subcutaneously on both sides near the trachea and the esopha-
gus. Near the height of the thyroid gland they almost touch the
carotid artery. They then cross, dorsalward, the trunk of the sub-
clavian artery, and in their course receive the vertebral vein and
unite with the subclavian vein toward the side of the vena brachio-
cephalica. The union on the right side lies to the right of the
anterior aorta, and the union on the left side lies to the left of the
pulmonary artery.

The jugular vein (Fig. 18, No. 4) receives in its course the follow-
ing veins:

The venz linguales (Fig. 62, No. B, 7), which at times empty
into the vena cephalica posterior.

The vena occipito-collares, which arises on the ventral side from
the muscles of the neck and the vertebra; empties into the vena
occipitalis lateralis and also communicates with the vena jugularis
by anastomoses.

The venz ascendentes laterales, which collect blood from the
lateral sides of the neck.

The venz colli cutinew, which enter the jugular vein laterally.
The upper branches are directed crosswise, and are shorter than the
lower ones. The lower branches are located near the thorax, are
directed upward, and anastomose by fine terminal twigs. Plexuses
are frequently formed in the inner side of the skin of the neck.

ANGIOLOGY 243

BRANCHES OF THE VENA SUBCLAVIA

Vena profunda ulnaris
Vena brachialis | Vena profunda radialis
{ Truncus vene Vena profunda humeri
axillaris
Vena basilica or cutinea ulnaris

( Vena cutinea abdomino-pectoralis
Truncus venz | Vena pectoris | Vena infrascapularis anterior
subclavie externa Vena thoracica externa

Vena coracoidea

Vena sternalis

The venz esophagez are numerous smaller veins formed in
closely woven plexuses in the region of the esophagus along the
neck. Some pass upward and some downward.

The venz tracheales are located on the supero-lateral side of the
trachea and along the edge of the lateral tracheal muscle. They
have numerous anastomoses transversely with the longitudinal
vein of the cervical region, anteriorly with the vena lingualis, and
on the left side with the left jugular vein.

The vena subscapularis passes along the median line of the scapula
to the side of the jugular vein, and anastomoses with the vertebral
vein.
The venz glandularum thyroidearum are several small, short
veins coming from the thyroid gland. :

The vena vertebralis, originating near the atlas, is a continuation
of the internal occipita’ vein. The internal occipital vein receives
the bulk of the blood from the brain and communicates with the
lateral veins of the cervical region and collects blood from the cer-
vical vertebra. The vertebral vein accompanies the vertebral
artery and the deep sympathetic nerve trunk in the vertebral canal.
The vein either leaves this canal with the vertebral artery at a point
near the last two vertebral nerve trunks of the brachial plexus, or
it leaves the canal one vertebra in front of the vertebral artery.

\

THE VEINS OF THE DORSAL REGION

The vena vertebralis lateralis dorsalis collects blood from the
cervical vertebre, from the dorsal vertebre, and from the inter-
costal region.

244 ANATOMY OF THE DOMESTIC FOWL

The blood from the neural canal, including the spinal cord, is
collected in one long vein extending from the head to the tail on
the upper side of the cord. This vein has sinus-like expansions.
Between each two vertebrz it anastomoses with the vertebral vein
on each side. In the lumbo-sacral region these anastomotic branches
empty into the hypogastric veins.

The vena intercostalis is formed in the costal region and anas-
tomoses with the vein extending longitudinally between the
capitulum and the tuberculum of the rib.

The vena vertebralis posterior at the height of the first and the
second dorsal vertebre, empties into the main trunk of the verte-
bral vein. Its lower roots come out near the side of the kidney,
and unite, forming a large ascending trunk uniting with the vena
vertebralis anterior forming one large trunk, which extends into the
chest cavity.

The posterior vertebral vein also receives a large vein from the skin
of the outer tarsal region and a few vessels from the muscles of
the outer abdominal and the outer costal region, from the skin,
from the pectoralis muscles, and from the shoulder region.

VEINS OF THE THORAX

BRANCHES OF THE VENA SUBCLAVIA

The vena thoracica externa (Fig. 73, No. 2) is made up of veins
mainly from the pectoral group of muscles. The posterior branch
anastomoses with the vena cutinea. Its anterior branch is made up
mainly of branches from the furcular region. It empties into the
vena pectoralis externa and the vena pectoralis externa empties into
the vena subclavia.

The vena coracoidea comes out of the region of the shoulder-
joint, passes downward along the inner surface of the coracoid,
and receives small branches from the walls of the arteria brachia
cephalica and from the pericardium.

The vena sternalis (Fig. 73, No. 1) is made up of two branches.
The outer branch comes from the muscles of the subclavian region
passes over the cristi sterni, medially, to the sterno-coracoid joint
and into the breast cavity, where it receives the inner branch,
which drains the inner surface of the breast-bone.

The vena thoracica interna empties into the vena cava anterior.
It extends from the abdominal muscles where it communicates with

ANGIOLOGY 245

the epigastric vein. It then passes on the inner side of the thoracic
cavity close to the breast-bone and receives many intercostal veins.

The vena cava sinistra receives first, the vena proventricularis
communis, which collects the blood from the walls of the proven-
triculus, and second, the vena coronaria cardis magna. This latter
vein originates close to the apex of the heart and collects blood
principally from the walls of the left ventricle. It connects in
the left sulcus transversus with the vena cardis superior and ends
at the base of the left upper vena cava. Its exit is not guarded
by a valve. The veins of the right ventricle are partly on the
surface. They collect blood along the sulcus transversus dexter
and enter directly into the right ventricle. The veins of the front
part of the heart are small. They collect behind the sulcus coro-
nalis and end either directly into the right auricle or into the vena
cardis magna.

VEINS OF THE FORE LIMB

The vena radialis profunda accompanies the radial artery on the
dorsal anterior rim of the index-finger and passes, on the dorsal
side, over the carpal region. It passes through the interosseous
ligament between the ulna and the radius, and reaches the ventral
surface of the arm. At this point it passes upward and anastomoses
with the vena ulnaris. It collects the blood from the skin of the
anterior wing region and the flexor muscles of the anterior arm. It
empties into the vena brachialis.

The vena humeri profunda (Fig. 68, No. 1) emerges at the height
of the elbow, and collects blood from the skin of the dorsal surface
of the wing. It also receives veins from the muscles of the posterior
side of the upper arm. It passes subcutaneously and dorsally over
the dorsal portion of the humerus in company with the external
radial muscle and passes with it around the external part of the hu-
merus between the long and short heads of the triceps. It takes a
diagonal course to the shoulder cavity and at that point empties into
the brachial trunk.

The profundus ulnaris originates at the volar surface of the hand,
proceeds in company with the ulnar artery, and sends on the base of
the hand small anastomotic veins to the vena cutanea ulnaris or
basilica. It passes along the anterior arm and between the flexor
carpi ulnaris and the pronator profundus muscle to the elbow-joint.
On the median surface of the biceps it passes upward and anastomo-

246 ANATOMY OF THE DOMESTIC FOWL

ses with the radial vein. The ulnar vein, in the region of the elbow-
joint, receives a large lateral branch which extends around the end
tendon of the biceps and anastomoses above with the vena basilica.

The vena basilica or cutanea ulnaris is a long vein which originates
from the subcutaneous dorsal surface of the index-finger. Near the
base of the hand it receives an anastomosing branch from the vena
radialis and the vena ulnaris, and then passes upward along the
posterior rim of the ulna. It receives numerous branches from the
roots of the flight feathers. It crosses below the elbow-joint and
reaches the volar surface of the arm. It receives a large branch
from the ulnar vein, and then, passing in a diagonal and median
direction to the triceps, extends to the shoulder cavity where it
empties into the axillary vein.

The outer breast veins unite forming a trunk which crosses ven-
trally to the subclavian artery, and empties into the subclavian
vein.

The vena cutanea abdomino-pectoralis collects the blood from a
large skin area of the abdomen, the upper thigh, the breast, and the
intercostal region. In the skin of the abdomen it forms a network.

BRANCHES OF THE ILIACS

Vena nietatarsalis* ( Vena metatarsalis
Vena © interna or magna plantaris profunda
tibialis | Vena tibialis antica

‘ postica | Vena metatarsalis
P f Venez metatarsales

' externa
2 Vena Vena metatarsalis dorsalis profunda
Vena tibialis | Vena metatarsalis dorsalis interna

poplitealis ; antica | Vena peronealis
Vena cutanea cruralis
Vene surales

Vena
iliaca Vena cutanea abdominalis femoralis
externa | Vena Vena femoralis interna profunda

cruralis Vena femoralis anterior
Vena epigastrica

The main trunk passes in the median abdominal line forward-and
then upward, along the outer edge of the pectoralis major, over the
first sternal rib; receives blood from the infrascapular vein, and emp-
ties into the pectoralis externa.

The vena brachialis is located in the middle of the humerus and

ANGIOLOGY 247

the triceps muscle. It is formed by the vena ulnaris, and the vena
radialis. It passes with the median nerve and the brachial artery
over the inner surface of the humeral joint. Posterior to the
humeral head it receives the vena profunda humeri. At the
shoulder cavity it receives the vena cutanea ulnaris or vena
basilica.

The trunk of the axillary vein is very short and is formed by the
veins of the shoulder and the wing. The deeper wing veins accom-
pany the large arterial and the nerve trunks.

BRANCHES OF THE VENA ILIACA INTERNA

( Vena intervertebralis lumbalis
Pars truncalis | Vena renalis magna

Vena hypogastrica caudalis si-

nistra
Vena renalis Vena hypogastrica caudalis dex-
tra ;
Vena portalis
Vena coccygea | Vena cutanea et pudenda
Vena iliaca Vena coccygea mesenterica
interna or Vena cutanea pubica
vena hy- | Pars caudalis | Vena cutanea caudalis
pogastrica Vena pudenda {Vena spermatica

Vena caudalis muscularis

Venez sacrales

Venez intervertebrales sacralis { Vene tenales
Venez renales

Pars renalis Vena ischiadica

Vena obturatoria

Vena supra-renalis externa [ Azygos sacralis

THE POSTERIOR VENA CAVA

The posterior vena cava (Fig. 63, No. 18; Fig. 70, No. 8) has its
origin in the posterior half of the body of the bird, somewhat to
the right of the posterior aorta, near the anterior lobe of the kidney,
by the wnion of the right and the left vena iliaca communis. It
receives the blood from all of the posterior half of the body including
the posterior limbs, of the visceral organs, of the abdominal and the
pelvic cavity. The posterior vena cava passes dorsally through
the right lobe of the liver and through the diaphragm and ends in a
short, broad trunk on the posterior dorsal side of the right auricle
of the heart. Its opening into the heart is guarded by two half-

248 ANATOMY OF THE DOMESTIC FOWL

moon shaped valves. The basal part of the trunk reaches from the
right auricle o the heart to the upper anterior rim of the liver where
it receives three large trunks, first, the right and second, the left
vena portalis hepatica magna, and third, smaller vessels from the
liver substance.

THE VEINS OF THE POSTERIOR EXTREMITY

In the skin region on the inner sides of the toes near their bases
the small veins collect into five metatarsal veins. The largest vein
collects the blood from the first, the second, and the third toe,
passes up the tarsus and is called the vena metatarsalis interna, or
vena magna (Fig. 65, No. 7). It is located just beneath the skin
on the inner surface of the metatarsal bone. It passes in a circle,
around the condyle of the tibia and becomes the vena tibialis postica
(Fig. 65, No. 3 and 8). The vena tibialis postica passes under the
tendon Achillis and the tendon of the flexor digitorum brevis, lies

BRANCHES OF THE VENA CAVA POSTERIOR

Vena ovariana
Vene testicule
Vena proventricularis communis
Vena suprarenalis revehentis
Vena portalis magna sinistra
Vena portalis magna dextra
Venez innominate
Venz hepaticz
Vena cava | Vena cardis coronaria magna
posterior | Vena proventricularis inferior
Vena iliaca interna oe hypogastrica.
Vena iliaca externa | Vena renalis
Vena supra-renalis externa
Vena iliaca | Vena ischiadica
communis | Vena renalis
Vena intervertebralis lumbalis
[ Vena renalis magna

‘ . _. { Vena coccygo-mesenterica
Vena mesenterica communis

Vena Vena mesenterica anterior
portalis | Vena pancreatico-duodenalis
dextra Vena proventricularis

Vena proventricularis lienalis
Vena splenica

Vena coccygo-mesenterica {Vena hemorrhoidalis

ANGIOLOGY 249

subcutaneously upon the latter, and reaching the knee-joint crosses
over the upper surface of the ischiadic nerve and becomes the
vena poplitealis, at which point it receives the vena tibialis antica.

On the dorsal side of the metatarsus are two veins. The vena
metatarsalis dorsalis profunda (Fig. 65, No. 11), which extends under
the tendon of the extensors of the toes, along with the artery and the
nerve. It collects the blood from the third and the fourth toe and in
the middle of the metatarsus receives the vena metatarsalis
dorsalis interna (Fig. 65, No. 4), which connects the vena metatar-
salis dorsalis profunda and the vena magna. The two dorsal veins
anastomose with the vena magna, at the intertarsal joint. They
pass transversely under the ligament and form the main trunk of the
vena tibialis antica which lies close to the anterior surface of the
tibia. Near this point there is formed a plexus of-veins which
again form a trunk and communicates with the vena peronealis and
enters between the tibia and fibula with the tibialis antica. It
extends along the flexure of the knee and the posterior part of the
lower thigh.

The vena metatarsalis externa passes subcutaneously on the
outside of the fourth toe and the metatarsus, and above the
intertarsal point joins the tibialis postica.

The vena metatarsalis plantaris profunda (Fig. 65, No. 5) lies
on the ventral side of the foot and forms several anastomosing
arches with the other veins of the toes. Below the intertarsal =
it enters the vena metatarsalis magna (Fig. 65, No. 9).

The vena cutanea cruralis (Fig. 69, No. 7) originates at the height
of the tarsal region and passes subcutaneously on the outer posterior
surface of the lower thigh region to the vena poplitealis.

The venz surales or inferior muscular branches of the vena poplit-
ealis consist of many veins. One branch comes from the region of the
shank and from the gastrocnemius muscle; another as a main branch
from the posterior surface of the lower thigh; and a third from the
outer surface of the muscles and skin of the upper thigh. The three
branches together with the anterior and posterior tibial (Fig. 60,
No. 2) unite at the flexure of the knee forming the vena poplitealis
(Fig. 69, No. 1).

In the region of the upper thigh, between the knee and the ab-
dominal cavity, the following four veins form the vena cruralis:
(Fig. 66, No. 6; Fig. 69, No. 5) First, the vena cutanea abdominalis
femoralis (Fig. 69, No. 6) which comes out of the side of the abdomi-

250 ANATOMY OF THE DOMESTIC FOWL

nal wall, draining the skin of the inner surface of the upper portion
of the thigh, the adductor muscles, and the region of the abdominal
and the breast border. It crosses the ischiadic artery in a diagonal
direction, and enters the vena cruralis in the middle of the crural
region.

Second, the vena femoralis interna profunda (Fig. 69, No. 3) forms
a communication between the end of the suralis near the knee. It
lies on the median portion of the flexor cruris internus muscle.

Third, the vena femoralis anterior (Fig..69, No. 4) is formed
from branches from the sartorius and adjacent structures, and
anteriorly empties into the crural vein near where the latter enters
the abdominal cavity.

Fourth, the vena epigastrica (Fig. 70, No. 33) is formed by branches
from the abdominal wall and branches from the walls of the abdomi-
nal air-sacs. It passes along the median surface of the os pubis
and ends into the vena cruralis near the spine of the ilio-pubica or at
a point where these join with the vena hypogastrica.

VEINS OF THE CAUDAL REGION AND OF THE PELVIC CAVITY

The vena iliaca interna or the vena hypogastrica (Fig. 70, No. 22)
collects most of the blood from the tail. The vena iliaca interna
collects most of the blood from the pelvic cavity, and the adjacent
intestines. It unites with the vena iliaca externa (Fig. 70, No. 27)
and receives the vena renalis magna and forms the trunk of the
vena iliaca communis (Fig. 70, No. 26).

The vena coccygea originates between the coccygeal vertebre,
and collects the blood from the region of the tail, including the tail
feathers, the tail muscles, the tail gland, and the skin of the region.
These small collecting vessels form a trunk on each side of the coccyx.
The right and the left pass laterally, each one taking up a vena
cutanea et pudenda, and frequently anastomosing with the vessels
on the other side. These often unite into one vessel. Both trunks
are connected by a transverse, or anastomotic, vessel. At this
anastomosis there empty into it the vena coccygea mesenterica and
the vena portalis. There also communicate at this point the right
and the left hypogastrica caudalis. In its course it is partly im-
bedded in the kidney and passes anteriorly to the vena iliaca com-
munis. This circle is called the arcus hypogastricus. Thus the

ANGIOLOGY 251

veins of the abdominal cavity have many anastomoses forming
many arcs, making possible two outlets for the blood.

The azygos sacralis empties into the arcus at about its middle.
From here it extends forward to the inside and under the kidney and
empties into the vena suprarenalis externa.

The vena cutanea pubica originates on the lower portion of the
abdomen, collects the blood from the muscles of the distal part of
the ischium, and enters the pelvic cavity between the ischium and
the ilium. It joins with the vena cutanea caudalis.

The vena cutanea caudalis originates from branches which drain
the skin and other parts of the ventral coccygeal region. The vena
cutanea pubica also communicates with the vena caudalis muscularis
and with the vena pudenda, thus forming the caudal trunk of the
vena hypogastrica.

The vena pudenda originates in the walls of the cloaca in the
region of the generative organs.

A small vena spermatica accompanies the lower end of the vas
deferens and the ureter, and empties medially into the vena pudenda.

The pars renalis of the vena hypogastrica extends from the middle
of the arcus to the union of the vena hypogastrica and the vena
cruralis.

The vena hypogastrica communicates with the pars renalis.
The vessels that empty into the pars renalis are as follows:

The venz sacrales collect blood from the dorsal wall of the
abdominal cavity and enter the pelvis through the foramen sacralis.
They pass between the pelvic wall and kidney, and at times pass
through the kidney tissue. They empty into the pars renalis of the
hypogastric arch.

The venz intervertebrales sacrales (Fig. 72, No. 2) originate
in the region of the roots of the plexus of sacral nerves and pass
through the kidney substance or on the dorsal surface and empty into
the pars renalis.

The vene renales (Fig. 72, No. 1) are very numerous and origi-
nate in the kidney substance, forming two main and several minor
branches, which pass posteriorly, and empty partly into the vena
hypogastrica, partly into the vena renalis magna, and also into the
vena intervertebralis; other branches empty into the trunk of the
iliaca communis.

The vena suprarenalis externa (Fig. 70, No. 30) is located near
the anterior rim of the kidney and is connected with the vena

252 ANATOMY OF THE DOMESTIC FOWL

hypogastrica. It also receives on the medial side, short branches
which come out of the upper kidney surface and sacral vertebra.

The vena ischiatica originates by the union of several venous
branches which come from the muscles of the pelvis and upper
thigh region. The ischiatic vein enters the pelvic cavity along
with the ischiatic nerve and artery, and communicates with the
vena hypogastrica at about. the level of the anterior lobe of the
kidney. It is always smaller than the vena cruralis.

The vena obturatoria originates mainly from vessels from the
obturator muscles. It enters the pelvic cavity through the obtura-
tor foramen. Another branch is sometimes found, which comes
out of the inner surface of the peritoneum which covers the obturator
muscles and the walls of the abdominal air-sacs and empties
between the vena ischiatica and the vena vertebralis into the
vena hypogastrica.

VEINS OF THE TRUNCUS VENA ILIACA COMMUNIS

The vena intervertebralis lumbalis, which comes out of the
lumbar region, the spinal canal, the lumbo-sacral nerve plexus, and
several small venous branches from the lobes of the kidney. It
passes dorsalward through the kidney and empties into the iliac
vein. There are also communications with the vena interverte-
bralis thoracica.

The vena renalis magna (Fig. 64, No. 47) forms the main descend-
ing vein to the middle and posterior lobes of the kidney. It lies
ventrally and mesially on the middle lobe and partly on the inner
part of the posterior lobe. It sometimes has on each side two main
trunks. The vein receives some small vessels out of the anterior
kidney lobe, also other small veins from that part of the peritoneum
which covers the kidney, from the rectum and finally small veins
from the ureter.

VISCERAL VEINS OF THE POSTERIOR VENA CAVA

The venz testicule, or the vena ovariana drain the blood from
the testicles of the male and ovary of the female.. The size of these
veins change with the enlargement of the testes or of the ovary
during reproductive activity.

-The ven supra-renales revehentes are short, thick trunks com-
ing from the adrenal glands. The left empties into the left side of

ANGIOLOGY 253

the posterior vena cava and the right into the right dorsal side.
These receive veins from the testicles in the male and from the ovary
in the female.

The vena proventricularis inferior drains the stomach wall. One
branch of this vein enters the left side of the posterior vena cava;
the other. enters the vena proventricularis communis, which in turn
empties into the trunk of the anterior vena cava sinistra.

The vene hepatice consist of one large and several small
veins from each lobe of the liver, and empty into the posterior
vena cava.

Some small vessels come from the pericardium and the peritoneal
covering of the liver, and pass in the mediastinum to the trunk of
the posterior vena cava.

In the region of the vena portalis:

The liver receives almost all. the blood from the stomach, the
intestines, the pancreatic gland, the spleen, partly from the liver
itself, and partly from the abdominal air-sacs. This blood enters
into the liver through the vena portalis dextra, the vena portalis
sinistra, and the vena portalis propria.

In both lobes of the liver these veins divide into numerous small
branches and collect again into two large short trunks, the vena
hepatica magna dextra (Fig. 70, No. 23), coming out of the right
lobe of the liver and the vena hepatica magna sinistra (Fig. 70, No.
24) coming out of the left lobe. These two vessels empty inferiorly
into the posterior vena cava.

The vena portalis dextra receives the blood from the vena mesen-
terica communis.

The vena mesenterica communis (Fig. 64, No. 36) receives the
blood from the vena coccygo-mesenterica (Fig. 70, No. 28) which
comes from the arcus hypogastricus and receives the vena hemor-
rhoidalis (Fig. 64, No. 37). This drains the cloaca and the bursa of
Fabricius, and it also receives veins from the rectum and from the
base of the czeca.

The vena mesenterica anterior (Fig. 71, No. 3) accompanies the
anterior mesenteric artery, and collects the blood from numerous
vessels from the small intestine.

The vena pancreatico-duodenalis (Fig. 64, No. 38) comes out of
the duodenum and the pancreas, along the right side of the stomach
and along both ceca.

The vena proventriculo-lienalis (Fig. 64, No. 39) comes out of

254 ANATOMY OF THE DOMESTIC FOWL

the dorsal side of the proventriculus on the left side of the gizzard,
passes along the hilus of the spleen, and takes up several splenic
veins. es

The vena portalis dextra (Fig. 64, No. 40; Fig. 71, No. 4) receives
a vein near the base of the gall-bladder. This branch enters the
right lobe of the liver and unites with the vena portalis sinistra.

The vena portalis sinistra (Fig. 71, No. 5) enters the left lobe of
the liver and there forms a sinus. It receives vessels which come
from the muscles of the gizzard, the inferior vena proventricularis,
and from the proventricular wall.

The vena portalis propria receives small veins which come out of
the walls of the abdominal air-sacs and from the fat of the abdominal
walls.

The vena umbilicalis originates in the umbilical region and empties
into the vena hepatica magna sinistra at a point where it comes out
of the liver (Fig. 70, No. 29). This is the remains of an embryonal
vein which collected all the blood of the yolk sac, passed on the left
side of the large intestine to the body, took up the vena mesenterica
and ended as the vena umphalo-mesenterica.

THE LYMPHATIC SYSTEM

The peculiarity of the lymph vessels is that they are associated
with organs in which lymph cells are formed.

The lymphatic system consists of the lymph vessels and the cell-
forming organs. In some instances the cell-producing organs are
lymph follicles and in others lymph glands.. For the most part the
glands are replaced by plexuses which in many places surround the
blood-vessels.

The lymph of birds is similar to that of mammals. The larger
lymph vessels are similar to.the veins, although the walls are always
thinner. Its tunica intima is rich in elastic fibers and has a layer
of endothelial cells on the inner side. The tunica media is formed
of rings of smooth muscle fibers. The adventitia is composed of
loose connective tissue.

The lymph vessels frequently form plexuses. The large lymph
trunks follow the course of the larger blood-vessels, and frequently
surround the arteries. All the lymph vessels of the body, exclusive
of the lymph of the caudal region, form into a large trunk which
originates on both sides of the celiaca communis and passes upward

ANGIOLOGY 255

along the side of the abdominal aorta, reaching a point anterior
to the celiaca. By receiving many vessels in this region it forms a
plexus around the aorta, and finally divides into two vessels, the
right and the left, ducti thoracici.

The lymph vessels of the left side of the head, the neck, and the
lung, and the left wing, and also lymph vessels of the proventriculus
and the throat enter into the left ductus thoracicus. They accom-
pany the jugular vein and are closely associated with the thyroid
gland.

The right thoracic duct receives the lymph veins from the right
cervical lymph vein, and the right side of the head, the neck, the
lung, ahd from the right wing.

After the right cervical lymph vein has passed through the right
thyroid gland, it divides into two branches, one branch emptying
into the right thoracic duct and the other into the vena cava dextra.

The lymph vessels of the liver, the stomach, the pancreas, and
the duodenum enter near the root of the arteria celiaca into the
large lymph trunk. The lymph vessels of the remainder of the
intestines, of the kidney, and of the generative organs empty farther
caudally. ,

The lymph vessels of the intestines take up the emulsified fat.
This emulsion in birds is colorless. The vessels pass upward along
the mesenteric arteries. There are no mesenteric glands. These
vessels form a plexus around the arteria celiaca. The lymph vessels
of the posterior extremities accompany the artery, especially the
anterior iliaca externa, and empty into the thoracic duct at the
point of the anterior iliaco-communis.

The lymph vessels in birds are numerous. The lymph glands are
few. They are only visibly found in the anterior breast and the neck
region, and sometimes in the wings. Lymph follicles are numerous
in the intestines.

The thin walls of the lacteals, of the lymph vessels, and of the
thoracic duct are made up of two tunics, the inner being the thinner
and weaker.

The lymphatics of the foot unite to form the vessels along the sides
of each toe. In palmipedes there are anastomosing branches which
pass from the lateral vessels of one toe to those of the adjoining toe,
forming arches in the uniting web of the foot. These branches form
a small plexus at the anterior part of the digito-metatarsal joint,
from which pass three or four lymph vessels. The anterior and

2 56 ANATOMY OF THE DOMESTIC FOWL

internal branches accompany and form a network around the
blood-vessels. The posterior and external branches receive the
lymphatic vessels from the sole of the foot. They then ascend
along the metatarsus and form, at.its proximal articulation, a close
network from which vessels pass along the tibial region, forming a
plexus around it as far as the middle of the leg: From this there
arises two branches. The smaller passes along the anterior part of
the depression between the tibia and the fibula, as far as the knee-
joint, where it joins the other branch, which accompanies the blood-
vessel. The trunk formed by the union of these two vessels ac-
companies the femoral vessels. Forming plexuses in its course, it
receives tributary vessels from the adjacent muscles. The iliac
trunk accompanies the femoral vein into the abdominal cavity,
entering just in front of the anterior end of the pubis. At this point
it recéives branches from the lateral parts of the pelvis and then
separates into two branches. The posterior vessel receives some
lymph from the anterior lobes of the kidney, and from the ovary, or
testis, and communicates anteriorly with a branch formed by the
lymph vessels adjacent to the anterior mesenteric artery, and
posteriorly with a large vesicular plexus surrounding the aorta and
its branches. This plexus receives the lymph from the renal plexus
and from those accompanying the arteria media.

There are two sacral or pelvic vesicles which are situated at the
angle between the tail and the thigh in the posterior part of the
abdominal cavity. Each vesicle is a trifle more than a half inch
long and a quarter inch wide, and is shaped somewhat like a kidney
bean. They have muscular coats with striated fibers. These sacs
are called ‘‘lymph hearts.” ;

The anterior division of the femoral lymphatic trunk accompanies
the aorta, on which it forms a plexus with the branches of the
opposite side, and with the intestinal lymph vessels. These vessels
commence from a continuous plexiform network located between
the mucous and the muscular coat of theintestine. They are larger
at this point than where they leave the intestine to pass through the
mesentery. They accompany the trunk of the anterior mesenteric
artery and form a plexus around it.

Before reaching the region of the aorta, the intestinal lympha-
tic vessels communicate with the posterior division of the femoral
trunk and with the lymph vessels of the ovary or of the testis.
After passing to the region of the aorta they receive vessels from

‘ANGIOLOGY 257

the pancreas and the duodenum, and terminate around the celiac
axis with the lymphatics of the liver, the proventriculus, the giz-
zard, and the spleen, forming a rather voluminous plexus (Lauth).

The aortic plexus represents the receptaculum chyli and gives
origin to two thoracic ducts, mentioned above, which passing on
each side of the bodies of the vertebrz, pass one right and one left,
over the lungs, from which they receive lymph vessels, and terminate
after receiving the lymph vessels of the wing, into the jugular vein
of their respective sides. The left thoracic duct, before emptying
into the vein, receives the trunk of the lymphatics of the left side of
the neck, and the right duct that of the right side of the neck, each °
tributary collecting lymph from all the structures of its side.

The lymphatics of the wing follow the course of the brachial
artery, forming a plexus around it. These vessels are well developed
in the eJbow region. The principal trunk, following the humerus,
receives collateral branches in its upper third. This vessel, when
nearing the chest, receives two or three large lymph vessels from
the pectoral muscles, and a branch which accompanies the brachial
plexus.

The lymph vessels of the head accompany the branches of the
jugular vein, collecting the lymph from the structures of the head
and the neck.

The lymphatic vessels communicate at the anterior and posterior
oblique anastomosing vessels. At the lower part of the neck each
trunk receives a vessel, which accompanies the carotid arteries.
Further on they are provided with a lymph gland which rests on the
jugular vein.

THE BLOOD AND ITS FUNCTIONS

The special function of the blood is to nourish all the tissues of the
body, and in this way to aid growth and repair. It furnishes mate-
rial for the purpose of the elaboration of body secretions; it supplies
the organism with oxygen; and it carries away carbon dioxid and
other effete material. Blood is constantly in circulation.

Blood is red, opaque, and is, in the fowl, quite viscid. The
exact tint of the blood. depends on whether it is drawn from an artery
or from a vein. Blood from a vein has a purplish tinge while that
from an artery is a bright scarlet. The color of blood is largely due
to pigment in the erythrocyte, called hemoglobin.

The reaction of the blood is alkaline, due to the phosphate and the

17

258 ANATOMY OF THE DOMESTIC FOWL

bicarbonate of soda. The alkalinity of the blood is reduced by work.
This is due to the formation of sarcolactic acid in the muscle. The
odor of blood is due to volatile fatty acids. Each kind of fowl
has its own peculiar odor. The taste of the blood is saltish, due
to a small amount of sodium chlorid it contains.

' The blood consists of the following substances:

First, the unorganized part, or fluid, the liquor sanguinis or
plasma. It contains in solution proteids, extractives, mineral mat-
ter, and gases. The gases are held in loose chemical union.

The liquor sanguinis constitutes fully 66 per cent. of the volume
of the blood. It is albuminous in nature and contains a small
amount of coloring matter of a fatty nature. It holds in solution
three proteids—fibrinogen, serum globulin, and serum albumin.

Second, the organized parts, or the cellular structure (Fig. 74,
Nos. 1 to 21). The cells float in the plasma and consist of three
groups: the erythrocytes, or red blood cells, the leucocytes, or white
blood cells, and the thrombocytes.

Erythrocytes.—The average number of red cells (Fig. 74, No. 21)
of the domestic fowl range between 3,000,000 and 4,000,000 per
cubic millimeter. The red blood cells are flattened and elliptical
in shape, and possess an oval elliptical nucleus. The average
length is 44100 inch and the diameter 14g99 inch, or 7 to 8 micra
in diameter and 12 to 13 micra in length. However the diameters
vary in different kinds of birds. The cytoplasm is yellowand glassy,
and the nucleus takes basic stains and appears somewhat picnotic.

Thrombocytes.—The thrombocyte (Fig. 74, No. 19) is of about the
same length as theerythrocyte but somewhat narrower. The nucleus
is round, stains purple with the Wright’s stain, and the chromatin
material is somewhat diffused. The diameter of the nucleus is
nearly equal to that of the cell. The cytoplasm is pale and may
show vacuoles near the nucleus. They may contain small circum-
scribed red structures. They vary somewhat in size and shape.
There are in the domestic fowl between 45,000 and 55,000 per cubic
millimeter.

Leucocytes.—There are, in the blood of the hen, 28,000 to 35,000
leucocytes per cubic millimeter. The leucocytes may be divided
into five distinct types. These are as follows:

Polymorphonuclear leucocytes with eosinophilic rods (Fig. 74, No.
2) are round and have a diameter about equal to the length of the
erythrocyte. The nucleus is polymorphous; that is, it has two or

li if
ih \y

2) ‘:
Nga

=
ra
\

1g

oo” 9%

Fic. 74.—Blood cells of the fowl. Wright's stain. From a S. C. Rhode Island Red cock-
erel. 1, Basophile (mast cell) with lilac staining spherical granules. 2, Eosinophile with
rod-shaped acidophile bodies. 3 and 4, Eosinophiles with acidophile staining round gran-
ules. 5, Eosinophile ruptured. 6, Mononuclear leucocyte with vacuoles in the cyto-
plasm. 7 and 9, Transitional leucocytes (first stage). 8, Mononuclear leucocyte. 10,
11, and 12, Smali lymphocytes. 13 and 14, Large lymphocytes. 15, A lymphocyte. 106,
Lymphocyte (nucleus centrally located). 17 and 18, Transitional leucocyte. 19, Throm-
bocyte. 20, Neutrophiie (polymorphonuclear). 21. Erythrocytes.

ANGIOLOGY 259

more lobes. The nucleus stains a pale blue, and the chromatin is
diffused. The cytoplasm is colorless with bright red staining spindle-
shaped rods. There are 28 to 32 per cent. of this type of cell in
the blood of the hen.

Polymorphonuclear leucocytes with eosinophilic granules (Fig.
74, No. 3 and 4) are of about the same shape and size as the preced-
ing. The nucleus is similar to the former except that it may
appear slightly picnotic. The cytoplasm stains not at all or faintly
blue; it contains round or spherical granules which stain a dull
red. ‘There is from 4 to 6 per cent. of this type of eosinophiles found
in the domestic fowl.

Lymphocytes are round in shape and of about the diameter of the
width of a. thrombocyte (Fig.. 74, No. 11). The nucleus is round,
staining somewhat purple, and contains a diffused chromatin material.
The cytoplasm exists in only small amounts; it lies to the side of the
nucleus and stains a pale blue. This is the small lymphocyte. A
similar cell but much larger also exists. This is the large lymphocyte
(Fig. 74, No. 13). There is from 40 to 44 per cent. of the lym-
phocytes in the blood of the fowl. The small lymphocytes are most
abundant.

Large mononuclear cells (Fig. 74, No. 6) either round or oval,
in shape, whose diameter may be about that of an erythrocyte and
at times much larger. The nucleus may be round, oval, or irregu-
lar, and at times rather crescent or U-shaped (Fig. 74,No.17). The
cytoplasm is abundant and completely surrounds the nucleus. The
cytoplasm stains a paler blue than the nucleus. Both taking the
basic stain as do the lymphocytes. These constitute 18 to 20 per
cent. of the cells of the blood.

Mast cells or basophiles (Fig. 74, No. 1) are of ‘about the same
size and shape as the eosinophiles. The nucleus is round or oval,
and stains a very pale blue. The cytoplasm is colorless, mostly to
one side of the nucleus, and contains round or spherical purple stain-
ing granules. This type of cell constitutes from 2 to 4 per cent. of
the white cells of the blood.

Structure of the Red Blood Cell.—The red blood cell is composed
of a spongy stroma holding in its meshes the red coloring matter.
The stroma, or framework, of the erythrocyte consists principally
of nucleo-albumin; it contains lecithin, cholesterin, and salts. The
red matter consists of an albuminous crystalline substance called
hemoglobin, which forms about go per cent. of the total solid matter

260 ANATOMY OF THE DOMESTIC FOWL

of the dried corpuscle. Each red cell offers a certain absorbing sur-
face for oxygen. As the blood circulates through the delicate walls
of the lungs and the air-sacs, it takes up oxygen; the blood at the
same time delivers to the air carbon dioxid which has been brought
from the tissues where active cell metabolism has been going on.
This oxygen taken up by the erythrocyte forms a loose chemical
union and is known as oxy-hemoglobin. In this form it is carried
to the tissues of the body where it is given up by the erythrocyte to
the tissues where oxidation is going on.

- Hemoglobin is a crystallizable proteid substance containing carbon,
hydrogen, oxygen, nitrogen, sulphur, and iron.

‘Formation of the Cells of the Blood—The red blood cells are
formed in the red marrow of the bone.

Polymorphonuclear leucocytes are formed in the red marrow of
the bones, and the lymphocytes in the lymph glands and lymph
follicles.

The bird carries a normal body temperature of 105° to 107° F.
The average temperature of 50 mature hens and cocks was 106.8° F.
The blood is of a deep red color.

Composition of the Blood.—The average composition of the blood
of the domestic fowl as given by Owen, is as follows:

Whole shed blood:

NE oa ock Rh aoa aed aware sisal 780 parts
CNG gc she nce so cetee ei iaale Peta ee een 157 parts
Albumin and salts............ Ranianamasmnainns 63 parts
Iooo parts
Moist blood cells:
Average total weight......................... 456.69
WES R 25 east esac cial deat tse psbadayen deena 342.52
SOV CET sose csecascce oe Soot academe a anaen led atin 97.50 ‘

piaemis
AN

Total welghtin..ccawmcugdaswemeserexees 543.30 parts
Watéfscerscsextsessecareseuersakasuretan 495.72 parts
SOLE MAES Lois snelane tomes sacs bi daw sass dase 30.72 parts

Blood when drawn and allowed to stand soon coagulates. In
the blood of birds this process is very rapid, the blood coagulating,
“in most instances, in about one-half minute. Blood coagulates only
.in the presence of calcium salts.

During life, the liquor sanguinis is termed plasma; but after it
has been shed from the body and coagulation has taken place, the

-

ANGIOLOGY 2601

liquid residue is called serum. Serum is plasma with its modifica-
tions as the result of coagulation, and as this latter process is
brought about by the production of fibrin, we may say that serum is
plasma minus fibrin-forming elements.

The proteids of the serum are serum globulin, serum albumin,
and a ferment produced as the result of coagulation. As fibrinogen
is used up in the process of coagulation, it is not found in the serum,
but there is in the serum a proteid known as fibrino-globulin. This
is produced from fibrinogen during the process of fibrin formation.
The following tabulation gives a clear idea of the difference between
the proteids of plasma and of those of serum:

Proteids of Plasma Proteids of Serum
Fibrinogen Serum globulin
Serum globulin Serum albumin
Serum albumin Fibrin ferment (nucleoproteid)

Fibrino-globulin

_ Fibrinogen is the percursor of fibrin.
The fibrin of the blood clot of the bird is soft and very lacerable.
The serum is usually yellow.

THE FATE OF THE ERYTHROCYTE OF THE FOWL

The power of vascular endothelium to ingest red blood corpuscles
has been studied by Keys.

When bacteria or other minute foreign bodies are injected into
the blood stream of pigeons, they are rapidly withdrawn from the
circulation into the tissues of the liver and of the spleen. The
foreign bodies are noted to be contained within cells of a distinct
type, whick is found in both liver and spleen. This type of cell
contains, in addition to the foreign substances injected, much yellow
pigment, and when tested for iron by Pearl’s method gives a positive
Prussian-blue reaction.

In such specimens there is a display of contrast to other tissues.
There is an extensive content of cells possessing the distinct tone of
Prussian-blue iron reaction. These cells are distributed rather
evenly throughout both the spleen and the liver, but more numer-
ously in the liver.

In the liver, under low-power magnification, these cells appear as
blue patches, sharply differentiated from the red-stained paren-
chyma. These cells are larger in their greater diameter than the liver

262 ANATOMY OF THE DOMESTIC FOWL

cells. They vary much in size and form. They bear a constant
.Telationship to the venous capillaries, and often appear to occupy
the lumen of the vessels. Under higher magnification it is noted,
however, that each. cell .is an integral part of the endothelial intima
lining of the capillaries. They are therefore fixed tissue cells, en-
gaged by one of its surfaces upon the reticulum of the vessel wall,
‘with a free surface bulging a greater or less degree into the lumen
of the vessel. The attached surface of the cell follows exactly the
line of the vessel wall. These cells are similar to those described
for mammals by Kupffer and are called Kupffer cells or stellate
cells. In the fowl Keys proposes the name hemophages. The
nucleus of the hemophage stains a deep garnet with the carmine used
in the above-given technic, and contains two or three very dis-
tinct and intensely stained nucleoli. In the hemophages, which are
more nearly flat, the nucleus appears like those of the typical endo-
thelial cells; whereas in the protruding hemophages of greater bulk,
the nucleus is more vesicular and is irregularly pyramidal in form.
Rarely two nuclei are found in one cell. Within this cell may be
seen vacuoles of the cytoplasm which contain red blood corpuscles.
These blood corpuscles have been phagocyted from the circulating
blood stream. Approximately one-third of the intimal cells are
hemophages. Each hemophage displays evidence that it contains,
or has recently contained, one or more red blood cells. The cellbody
of the hemophage has no fixed morphology, but changes from time
to time according to its phase of phagocytic activity. In a stage
which the hemophage has recently ingested a red blood cell, the
cell body bulges out into the lumen of the vessel and the nucleus is
crowded to one side. At this time the red blood cell appears as
those in the blood stream and possesses the characteristic staining
reactions. The nucleus of the red blood cell stains deep reddish
brown and the cytoplasm an even yellow bronze. In the next stage
the cytoplasm of the hemophage gives a diffuse Prussian-blue reac-
tion. Then in hemophages which represent later stages there are
various stages of disintegration and digestion of the red blood cell.
The first changes of the phagocyted red blood cell is hemolysis, the
hemoglobin escaping into vacuoles of the cytoplasm of the phago-
cytic cell, leaving the nucleus-containing stroma distinctly outlined.
The stroma may retain the original ovoid form or may become spher-
ical; the nucleus in such instances remains ovoid. Gradually, both
the stroma and nucleus lose their staining reaction until finally the

ANGIOLOGY 263

vacuoles contract about a small indistinct remnant of the nucleus,
which in its turn ultimately disappears. During this latter process
the size of the hemophage gradually decreases. The hemoglobin,
which has escaped into the cytoplasm of the hemophage, is seen to
undergo a series of changes. At first the greater part of the pigment
does not give the iron reaction but retains its yellow-bronze tone
with erythrosin and occupies vacuoles of various sizes. Later the
contents of the vacuoles give the iron react’on and with increasing
intensity. Later there is a gradual decrease in the staining reaction
indicating that the iron gradually disappears from the cells which
extracted it from the red blood cells it digests. As a summary we
find, that these cells take care of the worn out red blood cells. They
devour them; hemolyze them, destroying the stroma and nucleus;
split the hemoglobin and free the iron; and then finally return to
their normal form.

The spleen contains the same type cells, but they are fewer in
number. For the most part they are confined to the pulp cords and
have no such evident relation to the vessel wall, or lumen, as in the
liver.

The function of the cells of the spleen are essentially the same as
those in the liver.

Tron freed from the worn out red blood cells is not retained by the
cells freeing it, nor is it found in the bile. It does not occur else-
where in the tissues of the liver and spleen. It is possibly discharged
into the blood stream, and transported to the hemapoietic tissues.
Cells which hemolyze red blood cells and liberate the iron are to be
seriously throught of in connection with bile formation since bili-
rubin is approximately, if not identical with, iron-free hematoidon.

NEUROLOGY

The Nervous System.—The nervous system is an apparatus by
means of which animals appreciate and become influenced by im-
pressions from the outer world. Animals react on these impressions,
and thus are enabled to adapt themselves to their environment.
This system is the organic substratum of life, sensation, and motion.
Broadly stated, the nervous system connects the various parts of
the body with each other, and to codrdinate the parts into a har-
monious whole in order to carry on the bodily functions methodically
and to control the physiological division of labor throughout the
organism.

The nervous system consists of two parts. The first is the cerebro-
Spinal system, which comprises the central nervous axis, including
the brain and the spinal cord, and the peripheral nerves, including
the cranial and the spinal nerves. The second is the sympathetic
nervous system. The two parts of the system are closely linked
together, and both terminate in peripheral nerve endings, including
those of special sense, of sensation, and of motion.

The cerebrospinal nerves especially preside over the special senses,
motion and sensation; and the sympathetic over the digestive,
the pulmonary, and the vascular apparatus.

From a structural standpoint, the nerve system consists of cell
elements peculiarly differentiated from all other tissue cells in that
their protoplasm is extended in the form of processes, often to great
distances from the nuclear region. The cell elements are held in
place by supporting tissue and receive an abundant blood supply;
they are partly of ectodermal and partly of mesodermal origin.

The cell element of the nerve system, called a neurone, is the
developmental, structural, and functional unit of the. nervous
system. It is a single cell presenting unusual structural modifica-
tions. It comprises not only the nerve cell body with its numerous
protoplasmic processes, or dendrites, but also the axone, which may
vary in length from a fraction of a millimeter to fully half the bird’s
length. The bulk of the axone is many times the bulk of the cell
body.

264

NEUROLOGY 265

Certain non-medullated axones are surrounded by a delicate,
homogeneous, nucleated sheath, called the neurilemma, or sheath of

Schwann.
THE CRANIAL NERVES

The cranial nerves have their origin in the brain and leave the
cranial cavity in pairs. They are numbered numerically from before
backward, there being twelve pairs in all. The following is a tabu-
lation according to their number, name, and function:

No. Name Functional Nature
I. Olfactory Smell-sense
II. Optic Visual-sense
III. Oculomotor Motor to muscles of eyeball and orbit
IV. Pathetici Motor to superior oblique muscle of eyeball
V.. Trifacial Mixed: Sensor to face and tongue. Motor to face
VI. Abducentes Motor to External rectus of eyeball
VII. Facial Motor to muscles of head and face
VIIT. Auditory Hearing-sense
IX. Glossopharyngeal Mixed: Tongue, pharynx and muscles of throat
X. Vagus Mixed: Sensori-motor to respiratory tract and part
of alimentary tract
XI. Spinal accessory Motor to muscles of pharynx, neck and heart
XIT. Hypoglossal Motor to muscles of the tongue

Olfactorius.—Nervus olfactorius (Fig. 75, C, 16). This is the
nerve of smell, one of the nerves of special sense. The organ of
smell consists of five layers as follows:

First, a layer of olfactory fibers extending in different directions
and consisting of a dense plexiform arrangement of the axones of
the olfactory cells. From this layer the fibers pass into the layer
of olfactory glomeruli where their terminal ramifications mingle
with the dendritic terminals of cells lying in the more dorsal layers,
to form distinctly outlined spheroidal or oval nerve fiber nests, the
olfactory glomeruli.

Second, a.fine granular layer of basic substance containing round
cellular structures, the stratum granulosum.

Third, broader granular, or molecular layer, having on its inner
surface a row of large pyramidal cells which are both small and large
and which send their dendrites into the olfactory glomeruli. Their
points are directed outward.

Fourth, a layer of round cells tightly pressed together and measur-
ing about 5 microns in diameter. Between these cells are very
fine nerve fibers.

266 ANATOMY OF THE DOMESTIC FOWL

ut de
Fic. 75.—The brain of ahen. Photograph.

A. Upper surface of the brain. 1, Medulla oblongata. 2, Calamus scrip-
torius. 3, Cerebellum. 4, Opticlobes. 5, Transverse fissure. 6, Longitudinal
fissure. 7, Upper surface of the left cerebral lobe. 8, Upper surface of the
right cerebral lobe. 9, Lateral pillar of the cerebellum. :

B. The posterior surface of the eyeball. 1o, The sectioned surface of the
optic nerve.

C. The inferior surface of the brain. 11, Corneo-scleral juncture. 12, The
cornea. 13, The sclera. 14, The optic nerve. 15, The optic chiasm. 16, The
olfactory lobes. 17, The medulla oblongata. 18, Tuber cinererum et infundib-
ulum. ‘

NEUROLOGY 267

Fifth, a layer of epithelial cells.

The peripheral fibers and the nerve cell layers near the hemi-
spheres disappear so that the basic substance of the trabecula
with the hemispheres form the entire lobe mass. On the lower
surface of the hemispheres there is a long bundle of nerve fibers
which enter into the substance of the olfactory lobes and there
disappears. These fibers are medullated. Non-medullated fibers
enter into the makeup of the olfactory trunk.

The original center of the olfactory nerve is not in the hemisphere,
but in the same location as the optic nerve. This nerve trunk con-
sists of very fine non-medullated fibers. The nerves of smell are
therefore not peripheralistic nerves. The nerve fibers are distributed
to the mucous surface of the turbinated bones. Toward the front
they form an expanded prolongation.

The olfactory nerve, as it emerges from the cone-like anterior tip
of the cerebrum, is of considerable thickness and extends along with
the median dorsal artery of that region above and to the inside of
the orbit, under the thin bony structure. Before its termination
into the posterior turbinated bones, it is crossed by the superior
maxillary division of the fifth pair of cranial nerves. It extends as
far as the pituitary membrane of the turbinate bones upon which its
filaments are distributed radially.

The Opticus.—The nervus opticus (Fig. 75, No. C, 14) the second
cranial, is the nerve of sight. The optic lobe, or tuberculum
bigeminum lies at the base of the brain on each side of the optic
tract.

From the optic lobes the two trunks pass forward along the under
surface of the cerebri, forming the optic chiasm at the hypophysis
(Fig. 75, No. C, 15), at which point the nerve fibers originating from
the right side pass to the left, and vice versd. From the chiasm the
true optic nerves pass forward to the posterior surface of the eyeball.
They are composed of a bundle of very fine, marrow-like nerves.
These fibers enter into the ganglionic cells of the retina. By re-
moval of the finely adherent neurilemma, the optic nerve is seen to
be composed of parallel, longitudinal lamelle, the margins of which
are mostly free on one side.

The Motor Oculi—The motor oculi (Fig. 62, No. C, 10), the
third cranial nerve is a motor nerve. It originates close to the
base of the brain behind the position of the hippocampus of mam-
mals on the inner side of the crus cerebri, and also on the inner

268 ANATOMY OF THE DOMESTIC FOWL

somatic column close below and somewhat aside from the aqueduct
of Sylvius. The nerve leaves the brain cavity through a distinct
foramen near the foramen opticum, and supplies the following eye
muscles: first, after entering the orbit, it sends a branch upward
to the inferior portion of the inferior rectus; then, it gives off the
thick ramus ciliaris. The trunk then extends under the optic
nerve and passes forward to innervate the inferior rectus, the
internal rectus, and the inferior oblique. A ciliary ganglion forms
on the trunk.

The Patheticus.—(Fig. 62, No C, 11) is a small motor nerve,
originating close to the sulcus centralis, in the circle of the center
brain over the valve of Vieussens, between the posteriors of the
optic lobes. It extends in a dorsal direction between the cere-
bellum and the lobus opticus, to the posterior of the latter of
which it then forms a loop ventrally. Lying close to the optic
foramen it passes through a fine opening into the eye cavity and
supplies the superior oblique muscle of the eye. During its course
it passes dorsally over the optic nerve, and then crosses dorsally
over the ophthalmic division of the fifth pair of cranial nerves and
the internal rectus muscle.

The Trifacialis—(Fig. 62, No C, 12). This, the fifth cranial,
is a mixed nerve and is divided into two parts, portio major and
portio minor. ,

The portio major originates in the ganglion cells of the posterior
part of the brain. Commencing near the medulla oblongata it
passes through the posterior part of the brain, then upward and
outward; and along its route it forms the Gasserian ganglion, which
lies partly in the cranial cavity or in its wall.

The portio minor consists of the downward passing fibers contain-
ing the motoric elements which are distributed to the muscles of the
jaw and of the eye. The roots are found in the ganglion from the
center and back brain, close below the pathetic nerve origin, where
the pathetic passes between the lobus opticus and the pars pedun-
cularis; it then takes a lateral course between the two.

The fibers of the portio minor do not take part in the formation
of the Gasserian ganglion, but are only partly surrounded by it.

There are three nerve trunks given off of the trifacialis: the oph-
thalmic, the superior maxillary, and the inferior maxillary.

The ophthalmic division of the fifth nerve is the smallest of the
three branches. It emerges directly from the Gasserian ganglion,

NEUROLOGY 269

and passes through a narrow bony canal in the base of the brain,
‘below the pathetic and the abducens, and through the foramen
ophthalmicum. It then enters the eye cavity above the optic nerve,
and on the wall of the cavity extends downward, and with regard
to the eyeball, dorsally lying close to the rectus internus muscle
and close to the surface of the eyeball. It passes along the olfac-
tory nerve, extends under the superior olbique muscle, and finally
reaches the inner angle, or canthus, of the eye. It here divides into
the recurrent externa and the ethmoidalis. The ethmoidalis branch
is a straight continuation of the ophthalmic. It.extends along close
to its fellow of the opposite side, and, over the vomer, splits into two
branches. The smaller of these branches breaks through the bone
cells of the jaw, continues upon its ventral surface in a furrow ex-
tending forward, and terminates in the gum region. It supplies the
gum and point of the beak. The larger branch enters into the cell
substance extending to the tip of the beak, in its course sending
out a number of fine filaments, which spread out along the outer
surface. At this point these two branches may fuse. The larger
branch is endowed with the sense of touch.

The recurrent externa divides shortly after leaving the main trunk
of the eye cavity passes over the lacrimal gland. It gives two
branches to this gland and one to the membrana nictitans, and
innervates the upper eyelid. It then emerges from the eye cavity,
passing over the os lacrimale, and gives one or more branches to
the integument of this region, including the comb. This branch
is large in birds with a large comb. Branches pass in front of the
lacrimal bone through the outer nasal cavity and into its deeper
structure.

Shortly after the ophthalmic branch has entered into the eye
cavity and before it crosses the optic nerve, it gives a fine branch
to the motor occuli.

The second and the third branches of the fifth cranial nerve are
mixed. They contain elements of both the portio major and the
portio minor. These two branches come from the lower part of the
outer region of the ganglion, and pass together through a cavity
which is located between the os petrosum and ale and basis sphe-
noid, and then branch.

The ramus secundus, or superior maxillary division, of the tri-
facial, is the second branch and passes into the orbit below the
optic nerve and the eyeball. It is called the recurrent infra-orbitale.

270 ANATOMY OF THE DOMESTIC FOWL

It gives an ascending branch to the gland of Harder, one to the
conjunctiva, one to the membrana nictitans, and one to the eyelids.
It also gives a branch to the skin below the eye and to the angle
of the mouth. This latter branch is called the recurrent subcutaneous.
These two branches communicate with the recurrent nasal ciliaris
of the first trigeminus branch. The second branch passes below the
nasal opening, then passes on and forms the alveolar nerve on the side
between the gums. It sends several recurrent posterior branches
to the elevations on the back part of the mouth. It extends for-
ward to the point of the beak.

The inferior maxillary division of the fifth is larger than the
other two. It is directed downward and outward then upward to
the temporal region. At the temporal region it divides into five
parts. It gives a branch to the temporalis muscle, one to the
pterygoid muscle, and one to the mylo-hyoideus. The main branch
gives twigs to the parotid gland region and enters into the-dental
canal of the lower jaw. Numerous filaments break through the
lower jaw bone, and then spread out on the skin and rim of that bone.
The largest branch, called the recurrent maxillaris externa, comes
out near the coronoid process. The rest of the trunk extends to,
and comes out of, several foramina at the anterior point of the jaw
bone.

These filaments are contained in grooves or cavities of the
lower jaw and terminate in touch buds.

The trifacialis fuses with the other cranial nerves and with the
sympathetic nervous system. Some of these fusions are as follows:
The recurrent ophthalmica fuses with the orbito-nasalis ganglion.
Indirect fusion of the recurrent maxillary division of this nerve
takes place near the Gasserian ganglion through the sympathetic
nerves, the temporo-lacrimalis, the facial nerves, the large cervical
ganglion, and indirectly with the glosso-pharyngeal and the vagus.
This fusion has been called the superior recurrent branch of the
trigeminus, or trifacialis.

There is a direct fusion of the superior recurrent maxillary di-
vision of the fifth just before entering the upper jaw. This fusion
is with the spheno-palatine ganglion and the sympathetic carotidis
cephalica, and also with the large cervical ganglion.

The Abducens (Fig. 62, No. C, 13).—This nerve originates in the
somatic and motoric column along with the other nerves of the-eye
muscles. Its nucleus lies in the circle of the pars commissuralis of

NEUROLOGY 271

the cerebellum. The nerve then passes ventrally, as does the mo-
toris oculi and leaves the brain along the median line. This is a
comparatively large nerve and passes somewhat laterally and
ventrally from the foramen opticum through a canal in the sphenoid.
It then enters the orbital cavity. Some muscular twigs are given
off to the quadratus and to the pyramidalis muscle. This nerve
also innervates the external rectus muscle of the eye. The ab-
ducens anastomoses with the ramus ciliaris and the ophthalmic nerve
and gives fine nerve twigs to the ramus ciliaris externus of the cil-
iary ganglion.

The Facialis and the Acusticus.—The facial nerve originates with
the auditory (Fig. 62, No. C, 14 and 15) in a very vaguely known
manner, from the cerebellum. It divides into three parts.

The first of these probably comes from the complex ganglion with
the posterior roots of the auditory. This part belongs to the somatic
sensory group of nerves. From this same group originates the audi-
tory, which spreads out into the cochlea and takes the impressions
of sound. This nerve is short and thick, and, at the point where it
loses its medullary covering on entering the cochlea, there is devel-
oped a ganglion. This ganglion is similar to the spinal ganglia.

The second part is provided with one root which originates mesi-
ally and ventrally, from the deeper ganglion cells. Some of the
fibers from this root constitute the vestibular branches. They
accompany the auditory and supply the anterior part of the ear
labyrinth and the semicircular canals. The larger part of the
fibers of this trunk make up the intermediate part of the facial.
The geniculate ganglion is formed at their fusion. The sympathetic
spheno-palatine nerve emerges from this ganglion, coming out of the
aqueduct of Fallopius.

The third part, called the portio dura, is the main facialis. It is
located opposite the auditoria intermedia. Its roots may be traced
to the complex ganglion, from which they take a direction ventrally
from the median portion.

The facialis, after emerging from the aqueduct of Fallopius,
takes a curved course and partly fuses with the sympathetic temporo-
lacrimalis on the upper posterior wall of the ear drum. It is here
accompanied by the carotid and the cephalic arteries. It leaves
the ear drum through an opening in the quadrate bone, giving off a
large branch to the digastricus muscle and a small one to the sta-
pedius of the columella auris. The facialis trunk is quite large. It

272 ANATOMY OF THE DOMESTIC FOWL

then passes downward along the quadrate bone, where it receives a
large branch from the glosso-pharyngeus. This nerve also gives
branches to the mylo-hyoideus and the stylo-hyoideus muscle, crosses
laterally: the glosso-pharyngeus, and finally fuses with branches
of the subcutaneous and with the first, the second, the third, and
the fourth cervical nerves.. After this fusion the nerves innervate
the skin of the anterior of the neck and the constrictor colli muscle.

The facialis anastomoses as follows: with a fine. branch of the
sympathetic temporo-lacrimalis, indirectly with the ramus trigemi-
nus, with the large cervical: nerve ganglion and with the spheno-
palatine ganglion and nerve.

The Vagus Group.—The ninth, the tenth, and the eleventh cra-
nial nerves are by some anatomists called the vagus group, first so
called by Willis. They are made up of both sensory and motor
nerves.

_The Glosso-pharyngeus.—The roots of the glosso-pharyngeus (Fig.
62, No. C, 16; Fig. 76, No. 13) emerge, along with those of the vagus,
from the medulla oblongata, and enter, as a short trunk, the foramen
jugulare et caroticum. Between these two nerves there is usually
found a thin portion of bone. ‘The trunk of the glosso-pharyngeus
forms a ganglion in the foramen jugulare et caroticum where it
receives connecting branches from the near-by ganglion radicis and
vagus nerve. The glosso-pharyngeus passes out of the foramen
jugulare et caroticum above the large superior smpathetic nerve gan-
glion, with which it communicates. The glosso-pharyngeus passes
diagonally over the ramus temporo-lacrimalis of the sympathetic
system, and then receives a very strong branch from the vagus (Fig.
76, No. 12). It sends a short branch to the recurrent lacrimalis of
the sympathetic system. At this point there is formed a reddish-
yellow ganglion, the petrosal ganglion, which is similar to the petrosal
ganglion of mammals. Frequently it is found close below the large
superior cervical nerve ganglion. The petrosal ganglion is fre-
quently connected by special fibers with the cervical nerve ganglion,
the large superior cervical nerve ganglion and the ganglion radicis
vagi. The glosso-pharyngeus is divided into the following branches.

First, the recurrent pharyngeus which gives branches to the upper
part of the throat and which is tortuous in its course. It receives
a branch from the superior cervical nerve ganglion and gives off
branches to the salivary glands and papille of the posterior tongue
region.

273

NEUROLOGY

Second, the recurrent lingualis, which passes with the lingual

artery over the hyoid bone to the base of the tongue and to the

papille.

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274 ANATOMY OF THE DOMESTIC FOWL

in the foramen through which it passes. The foramen lies between
the os petrosum and os‘occipifale, close to the foramen jugulare,-
above and to the inside of it..

~The ganglionic root of the vagus communicates with the superior
cervical nerve ganglion. The vagus, after coming out of the foramen,
takes up branches of the spinal accessory, passes to the superior
nerve ganglion, crosses the carotid artery, and then, ‘accompanied
by the internal jugular, it connects by a branch with the hypoglossal.
It then communicates with the petrosal ganglion, and receives a
long branch from the superior cervical ganglion. It then extends
along the neck with the jugular vein and often fuses with the sym-
pathetic ganglionic plexuses. As it passes, it is interwoven with the
glosso-pharyngeus, but each nerve element retains its own individu-
ality. Extending down the neck, on entering the thoracic cavity,
it lies between the plexus brachialis and the carotid artery. Then
it passes below the subclavian artery, and between the bronchial
tubes, the aorta pulmonalis, and the subclavian vein. Then ven-
trally it rests upon the glands, and the right and the left vagi fuse
or unite. From here they radiate down to the stomach in fan shape,
and, continuing, they fuse with the sympathetic system.

The other branches of the vagus are:

The first branch is the recurrent laryngeus, which supplies the
lower end of the bronchial tubes, and the esophagus, then enters
above the bronchus near the origin of the subclavian artery as the
recurrent cardiacus.

The second are the recurrent pulmonale which pass into the lungs,
each fusing with its fellow from the opposite side, and giving off
branches inferior to the vena cava including a branch to the heart.

The third are the recurrent hepatici which pass through the dia-
phragm and are distributed to the liver.

The Accessorius Spinalis.—This is a very small motor nerve
(Fig.62,No.C,18). It comes out between the dorsal and the ventral
root of the third cervical nerve. It lies close tothe neck and extends
anteriorly, receiving roots from the first and the second cervical
nerve. It passes through the occipital foramen into the brain cavity
and then enters the ganglion radicis vagi. It passes out of the cranial
cavity through the foramen jugulare. It then partly fuses with the
vagus and partly, as a fine branch, with the subcutaneous colli. z

The Hypoglossus.—The hypoglossus is a motor nerve (Fig. 62,
No. C, 19). It originates anterior to the eleventh pair of cranial -

NEUROLOGY 275

nerves, and from the same ganglion as the abducens'and ‘thé motor
oculi. It leaves the medulla oblongata from its ventral surface, and
passes with a posterior and an anterior branch out of the cranial
cavity through two separate foramina in the os occipitale laterale.
The postérior branch, much smaller than the anterior, passes between
the cranial bones and the cervical sympathetic nerve; it then passes
at right angles through the rectus capitis anticus, and, while closely
following the ‘carotid artery, it fuses with the anterior branch,
The larger, anterior branch, much stronger than the posterior, sends
a short strong branch to the complexus muscle. The rest of this
branch, which probably has sympathetic‘elements, is disposed as is
a spinal nerve. It crosses the sympathetic nerve, and at this point
forms a typical cervical sympathetic ganglion. It also forms a
short loop with the recurrent ventralis of the first cervical. plexus.
From this loop, after it has given off several branches to the
muscles of the neck, it gives off one or two strong branches, which
fuse with each other and with the posterior thin branch, thus form-
ing the trunk of the hypoglossus. It receives many elements from,
the first cervical nerves. i :

The hypoglossus sometimes communicates with the vagus, crosses,
over the latter, and divides itself into two main branches, as follows:

First, the recurrent laryngo-lingualis, which passes between the
cornua of the os hyoideum and the larynx to the anterior part,
and furnishes the principal tongue muscles. It extends along the
inferior.surface of the tongue and fuses with the one of the other
side and extends to the free tip of the tongue. This nerve probably
receives sensory elements from the second root and from the con-
fluent of the first cervical nerve. This form of anastomosis is well
marked in birds with thick tongues,.as ducks.

Second, the recurrent laryngeus furnishes the muscles of the su-
perior larynx and of the tongue skeleton. It extends downward
and also furnishes the muscles of the trachea. It follows the course

- of the jugular'vein and at the entrance of the chest supplies the fur-
cula. The nerve passes into the thorax,.downward along the side of
the bronchial tubes, and supplies innervation to all the muscles of
the inferior larynx.

THE SPINAL CORD

Structure of the Cord.—The spinal cord is called the myelon or
medulla spinalis. It is a comparatively large, white, irregularly

276 ANATOMY OF THE DOMESTIC FOWL

cylindrical cord, flattened from above downward. It extends from
the foramen magnum at the base of the medulla to the caudal portion
of the spinal canal where it terminates in a fine filament. In order
to allow considerable motion of the spinal column without danger of
injury to the spinal cord, the cord is loosely suspended in the canal.
The meninges, or coverings, are continued from the brain. In addi-
tion to these there are to be found arteries, veins, and nerves en-
tering and others making their exit from the canal and from the
cord. At the cervico-dorsal juncture, where the brachial plexus
is given off, the cord is enlarged. There is another enlargement at
the point where the lumbo-sacral plexus is given off. At this point,
superiorly, there is a longitudinal cavity called the sinus rhomboi-
dalis. This sinus contains a gelatinous substance. There is a pair
of nerves given off at each intervertebral foramen. ‘Thus there are
as many pairs of spinal nerves as there are vertebral segments. The
inferior root is the motor root and ¢arries the impulses from the
cord to the periphery. The superior root is the sensory branch
and carries the impulses from the periphery tothe cord, and thence
the impulse is carried to the ‘centers in the brain. The sensory.
and the motor roots are of about equal size. The inferior have more
numerous filaments. The ganglion on the superior or sensory root
is relatively large. In the sacral region the sensory and the motor
branches pass through their own bony canal.

White rami communicantes are given off at each intervertebral
foramen to the sympathetic system and gray rami are received from
the sympathetic ganglia. Thus there is established a direct commu-
nication between the sympathetic and the spinal system. There isa
ganglion on the superior root just outside the spinal cord.

The ganglionic portion, or gray matter, is arranged in the center
of the cord in two comma-shaped parts forming an X. The white
matter, or the material forming the fibers, is arranged around the
central ganglionic portion.

The spinal cord may be divided into two lateral symmetrical
halves. There are two longitudinal fissures, one on the upper and
the other on the lower half. The upper called the superior median,
fissure is narrow but deep. The one on the inferior side, called the
inferior median, is usually more pronounced. The superior parts
of the gray matter are called the superior cornua, or horns; the
inferior parts the inferior cornua, or horns. The center of the cord

NEUROLOGY 277

is pierced by a central canal which communicates with the fourth
ventricle at the calamus scriptorius.

STRUCTURE OF THE NERVE TRUNKS AND GANGLIA

The protoplasmic processes called dendrites ‘have a similar struc-
ture to the cell body. The dendrites branch dichotomously, become
rapidly smaller, and usually end at no great distance from the cell
body.

The axone or axis cylinder process, differs from the cell body and
from the dendrites. It does not contain chromophilic granules.
It consists entirely of neurofibrils and perifibrillar substance. It
emerges from the cell at an enlargement known as the axone hill.
This hill is free from chromophilic bodies.

Nerves are divided into two kinds, medullated and non-niedullated.

Medullated nerves are divided into two kinds: medullated nerves
with a neurolemma, and medullated nerves without a neurolemma.

Medullated nerves with a neurolemma consists of an axone, a
medullary sheath, and a neurolemma. A delicate membrane called
an axolemma, or periaxial sheath envelops the axone. The medullary
sheath called myelin, is semifluid, somewhat resembling fat. The
outer covering is the neurolemma, or sheath of Schwann. It is a
delicate, structureless membrane which incloses the myelin. There
is under this sheath an occasional oval nucleus. At intervals there
are constrictions, or nodes, called the constrictions of Ranvier. The
part between the nodes is called the internode.

The medullated axones without a neurolemma are the medullated
nerve fibers of the central nervous system.

The non-medullated axones, or non-medullated nerve fibers, are
divided into non-medullated axones with and those without, a neuro-
lemma.

The non-medullated axone without a neurolemma is merely a naked
axone. They are confined to the gray matter and to the beginnings
and endings of sheath axones, all the latter being uncovered for a
short distance after leaving the nerve cell body and also just before
reaching their terminations.

The long axones serve to make connections with the peripheral,
or distant, nerve cell, muscle cell, or gland cell; while the shorter
axones of certain neurones divide into terminal branches in the
immediate vicinity of its cell body, presumably to come into relation
with other nerve cells in the same or adjacent groups.

278 ANATOMY OF THE DOMESTIC FOWL

alt Aes TOMS EAI my

re il i ea
aoe si

Fic. 77.—Histological structure of tissues.

a _Non-striated or involuntary muscle cell. a. 1, Nucleus; 2, Protoplasm.
b. Transverse section showing nuclei in the center of the cells that are cut
through the nuclear zone. c. A cross-section of the connective tissue which
‘binds together the muscle-cells. d. A section showing the so-called intercellular
bridges. :

**'2. A cross-section of the rectus abdominalis. 1, The endomysium which binds
‘the cells into primary fasciculi or bundles. 2, The perimysium which surround
the bundles of fasciculi. 3, The epimysium which surrounds the muscle. These
‘binding structures are white fibrous connective tissue.

3. A longitudinal section at.the juncture of a muscle and tendon. a, The

NEUROLOGY 279

Neurones are devoted to the maintenance of functions. Repro-
ductive neurones are so arranged as to receive afferent nerve impulses
from other tissues; emissive neurones give off efferent nerve impulses.
The. former are sensory neurones; the latter are motor neurones
if connected with muscles, and excito-glandular if connected with
gland cells. The basis, then, of the nerve system is a series of neu-
rones, with projecting and association processes, codrdinated for
the purpose of performing specific actions manifested either by
motion, by trophic changes, or by the apperception of stimuli of
a chemic, mechanic (tactile and auditory), thermal, or photic nature.

The whole of the nerve structure is composed of the nerve tissue
and supporting connective tissue. The neurones constitute the
nerve tissue, while the supportive tissue is composed of neuroglia
and of white fibrous tissue derived either from the investing mem-
brane or from the sheaths of its numerous vascular channels.

The neurones, or nerve cells, exhibit marked variations as to ex-
ternal characters, dimensions, and form. The neurone presents a
swollen cell mass and a‘nucleus; it is known as the ganglion cell.
From this cell body are given off a number of processes of two dis-
_ tinct kinds: first, protoplasmic processes, which are commonly
branched, called dendrites; second, a single, thinner, and paler proc-
ess; the axis cylinder process.

juncture between the muscle and tendon. Note the many nutlei in both muscle
and tendon. This is voluntary or striated muscle which make up the dermal,
dermo-osseous and skeletal muscles.

4. A longitudinal section of heart muscle. a, Connective-tissue cell. 0},
Nucleus of a muscle cell. c, Cement line between the muscle discs. d, The
cell or segment.

5. A bipolar ganglionic nerve cell. a, The nucleus. 6, The nucleolus. c, The
fibrillar structure. d, The medullary sheath. 3S

6. A diagram showing the scheme of the peripheral nerve trunk. «@, The
neuraxis of the peripheral:sensory neurone. 0b, The spinal ganglion of the
superior or sensory root. c, The dendrite or peripheral nerve fiber of the sensory
nerve. d, The nerve trunk. f, The sympathetic nerve ganglion connected with
the spinal cord through the white and the gray ramus communicans. e, The
‘neuraxis of the sympathetic neurone. g, Neuraxis or trunk of the motor neurone
or nerve cell. h, The anterior horn of the gray matter of the spinal cord.

q. A diagram of a peripheral sensory neurone. u, The neuraxis which ends
in the spinal cord or brain. 6, The T-shaped division of Ranvier. c, The den-
drite or sensory nerve fiber in the nerve trunk. d, The nucleus and nucleolus
of the cell ¢., f. the axis cylinder process of the cell. g, The telodendrions or
terminal branches of the dendrite or axis cylinder.

8. A schematic diagram of the sensory motor reflex. a, The telodendria.
b, The dendrite. c, Nerve cell of the motor neurone. d, The motor neurone.
f, The muscle fiber. g, The neuraxis of both sensory and motor neurones, the
upper being the sensory. h, the nerve cell in the sensory ganglion. i, The
sensory neurone or axis cylinder (nerve fiber). j, The skin with peripheral
telodendrion of sensory neurone.

280 ANATOMY OF THE DOMESTIC FOWL

The bodies of cells vary in size from 4 to 100 microns or more in
diameter. The largest cells occur in the inferior horn of the spinal
cord, in the spinal ganglia, in the large pyramidal cell layer of the
cerebral cortex, in the Purkinjean cell layer ‘of the cerebellum, and
in Clark’s column of the spinal cord. Very small cells occur in the
olfactory bulbs, in the granular layer of the cerebral and cerebellar
cortex, and in the gliosum cornuale of the cord.

Nerve cells are classified according to the number of processes
arising from the cell body, and neurones are referred to as unipolar,
bipolar, and multipolar.

Unipolar cells are met with frequently in early stages of em-
bryonic development, but are rare in adults, occurring only in the
retina, in the olfactory bulb, and within the baskets of the Pur-
kinjean cells of the cerebellum. The cells of the cerebro-spinal
ganglia, except the cochlear and vestibular, are apparently uni-
polar, but they are developmentally and functionally of bipolar
nature. :

Bipolar cells are found almost exclusively in. the peripheral sen-
sory system, as in the olfactory membrane, in the retina, in the coch-
lear and vestibular ganglia, and in the cerebrospinal ganglia of the
embryo.

Multipolar cells are the most numerous and form the principal
elements of nerve centers throughout the system: - They are termed
multipolar because of the greater or lesser number of dendrites
given off in addition to the single axone.

The body of the nerve cell consists of a mass of protoplasm sur-
rounding a nucleus. The.cytoplasm of the nerve cell consists of
two distinct substances: first, neurofibrils; second, perifibrillar sub-
stance. In most nerve cells there is a third substance called chro-
mophilic bodies.

The neurofibrils, extremely delicate, are continuous throughout
the cell body and all of its processes. Within the body of the celt
_ they cross and interlace and probably anastomose.

The perifibrillar substance is a fluid or a semifluid substance which
both in the cell body and in the processes surrounds and separates
the neurofibrils.

The chromophilic bodies are granules or groups of granules which
occur in the cytoplasm of all the larger and of many of the smaller
nerve cells.

NEUROLOGY 281

THE SPINAL NERVES

The first pair of spinal nerves come out between the atlas and the
occipital bone. Each nerve divides into three branches. The first
is the anterior branch which innervates the dorsalis, the biventer
cervicis, the cervicales, and the caput posticus muscles. The sec-
ond is the recurrent ventralis which passes mesially and downward
from the recurrent communicans. It innervates the rectus capitis
anticus muscle and joins a branch of the hypoglossal nerve. There
is given off a white ramus communicans to the sympathetic nerve.

The second spinal nerve emerges from the opening between the
first and the second cervical vertebre and is similarly disposed as
the first cervical. It gives off a branch called the recurrent ventralis
which fuses with branches of the first cervical and the hypoglossal
nerve. This nerve innervates the complexus muscle.

The succeeding cervical nerves emerge in a similar manner down
the neck and are distributed to the muscles and other structures of
the cervical region. The second, the third, and the fourth cervical
nerve gives off branches which form anastomosing loops with the
facial nerve. :

According to Gadow the last cervical nerve passes between the
last cervical and the first dorsal segment. There are thus fifteen
pair of cervical nerves.

The first pair of dorsal nerves pass out between the first two dorsal
vertebra. The first few dorsal nerve branches innervate only the
trunk muscles. Other branches supply the skin and the other
adjacent integument. The ventral branches of the cervical nerves
often communicate with the ventral branches of the first dorsal
nerves. These branches are larger than the superior branches and
aid in the formation of the bracial plexus. Smaller inferior branches
are distributed to the scalenus and other muscles, and extend as far
posterior as the intestines.

The dorsal branches of the spinal nerves in the lumbo-sacral
region are very small, on account of the lack of extensive develop-
ment of the muscles of this region. ~ The elements entering into these
nerve trunks are largely vasomotor nerves. In addition to the
upper twigs supplying the skin and the other integument of the
-region, other branches descend into the abdominal cavity.

The caudal spinal nerves are not well developed and disappear
in the region of the caudal vertebre. The dorsal branches inner-

282 ANATOMY OF THE DOMESTIC FOWL

vate the levator muscles, and the ventral branches the depressor
muscles.

There is thus given off, throughout the vertebral column, a pair
of nerves between each two vertebral segments, making as many
pairs of nerves for the region as there are vertebral segments of
that region.

The Brachial Plexus.—The brachial plexus (Fig. 73, No. 19)
arises principally from the roots of the last three cervical and the
first dorsal spinal nerves. These branches anastomose beneath the
deep face of the scapulo-humeral articulation.

The brachial plexus divides into two distinct parts. The first
(Fig. 73, No. 20) the dorsal called the superior thoracic is distributed
to the serratus and the rhomboideus muscle. The second is the
inferior thoracic (Fig. 73, No. 21), which consists of the main plexus,
and which gives off muscular branches especially to the sterno-cora-
coideus and to the main portion passing on as the nerve trunk to
the structures of the wing.

From the superior thoracic plexus there are several BECOBUATY...
plexuses formed.

The dorsalis or serratus plexus. This plexus is located adjacent
to the anterior part of the main plexus and is formed of from two
to four spinal nerve branches. The rhomboideus is supplied by
branches which may be traced to the first root of this plexus:
This nerve is called the rhomboideus superficialis. Another nerve
is given off from the middle part of the dorsal side of the plexus
and is called the rhomboideus profundus. A third, the superficialis
serratus, is the largest of the branches. It breaks up into terminal
branches, one going to each serration, or digitation, of the serratus
muscle. Branches from the anterior portion of this plexus are dis-
tributed to the patagii muscles.

The superior brachial plexus: gives off the following nerves:

The subcoraco-scapularts, which is purely a motor nerve, springs
from the anterior roots of the plexus. It gives off a branch to the
following three muscles: subcoracoideus, subcoracoido-scapularis,
and scapulo-humeralis. ,

The scapulo-humeralis is distributed to the scapular humeral
region.

The Jatissimus dorsi is located on the peripheral border of the scap-
ulo-humeralis or supra-spinatus. It originates from the second,
and the fourth nerve roots of the plexus: It is located on the dorsal

NEUROLOGY 283

side of the plexus. It divides into two main branches, one going
to the latissimus dorsi and the other to the scapulo-humeralis
muscle. From the side are given off branches which supply the
patagii muscle and enter into the formation of the dorso-cutaneous
plexus.

The axillaris springs from the second and the third root of the
brachial plexus, extends in a lateral direction, passing the ventral
and distal rim of the insertional part of the posterior scapulo-hu-.
meralis or teres et infraspinatus and enters near the capsular liga-
ment of the shoulder-joint. It gives off to this joint a small branch,
called the recurrent articularis, which passes outward between the
triceps brachialis and the humerus. It lies on the inner side of ‘the
major deltoid, and patagii muscles, and also the skin of the lateral
shoulder and the upper arm region. The recurrent axillaris commu-
nicates with the main branch of the radial nerve.

The cutaneus brachii superior is a small nerve which springs
from the last brachial plexus root and passes between the skin and
the triceps brachii muscle on the dorsal surface of the upper arm,
or brachial, region. It extends down over the elbow region, where
it gives off numerous branches to the skin of these regions, to the
meta-patagium and to the extensor muscles of the upper arm.

The brachialis longus superior is a large nerve trunk which springs
from most of the other plexus roots. It extends around to the
dorsal side of the upper arm and supplies the skin, the feathers, and
the muscles of the forearm and the hand. Branches from this nerve
trunk supply the triceps brachii and other muscles of the region.
The main branch passes between the radius and the ulna, and, pass-
ing the elbow-joint, gives off branches to that joint. Passing on, it
divides into two branches. One of these extends superficially over
the upper part of the condylus ulnaris and supplies the extensor
digitorum communis and the extensor metacarpi ulnaris, or flexor
metacarpi radialis muscles, and, continuing superficially to the
ulnar side, is distributed to the skin of the region. The second, a
deep branch, extends on the ulnar side of the radius over the ex-
tensor indicis longus, and innervates the latter muscle, the extensor
pollicis. longus, the extensor pollicis brevis, the adductor pollicis, the
interosseous palmaris, and the flexor digitorum.

The inferior brachial plexus gives off the following branches:

The supra-coracoideus, a large nerve which springs from the

284 ANATOMY OF THE DOMESTIC FOWL

first main root of the plexus, and passes outward through the fora-
men coracoideum of the sternal ligament. ‘

The sterno-coracoideus, a small nerve which extends downward
from the plexus.

The somewhat large posterior coraco-brachialis, nerve which
springs from one or two middle roots of the plexus and accompanies
the pectoral nerve. ;

The anterior thoracic, a large nerve which springs frem two or
three of the posterior roots of the plexus and extends to the shoulder
cavity where it branches. The anterior branch is distributed to
the patagium and the front part of the pectoral muscles. The
posterior branch supplies muscles along the side of the thorax and
extends into the abdominal muscles.

The anterior coraco-brachialis, a small nerve which springs mostly
from the inferior longus brachialis, passes to the distal end of the
tuberculum humeralis radii, then passes backward between the
front part of the humerus and the biceps, where it supplies the
anterior coraco-brachialis.

The cutaneous brachialis et inferior brachialis, a small nerve which

springs from the posterior roots of the plexus. It is distributed to
the skin of the region and branches are given off to the patagii and
the ventral wing surface. A few branches extend as far as the upper
arm.
The brachialis longus inferior (Fig. 68, No. 2), a continuation of
the main trunk of the inferior brachial nerve, which comes out of
all the plexus roots except the first. It gives off some branches to
the pectoral region and then enters the shoulder cavity. It gives
off the anterior coraco-brachialis, passes down the humerus in an
S-shape, and divides into two branches, the ulnar and the median.

The ulnar nerve (Fig. 67, No. 3) divides into numerous branches
which are distributed to the ulnar side of the forearm and the hand.
The ulnar nerve passes below the skin of the ulnar outside rim of the
forearm and gives branches to the carpi ulnaris, finally supplying
the flexor digitorum; it then passes with the tendon of this muscle
downward to the interosseous dorsalis, the abductor indicis, or
flexor minimi brevis, the flexor pollicis, and the abductor pollicis,
or extensor proprius pollicis.

The median nerve (Fig. 67, No. 2) extends down the arm and gives
branches to the biceps muscle, and to the patagii region. Continu-
ing, the median nerve supplies the pronator muscle and the brachi-

NEUROLOGY 285

a

alis inferior, or brachialis anticus, and then divides into two branches.
The first and largest branch passes between the two pronator muscles
giving branches to the pronator profundus, or pronator longus, and
the flexor digitorum profundus muscle. This nerve then passes
anteriorly along the tendon to the base of the digit, and, on the
dorsal side, joins the other branch of the median nerve. At this
point there is often a plexus, and at the point of fusion of the ulnar
nerve on the ulnar side there may also be a small plexus. These
plexuses mainly supply .the skin of these regions. The second
branch, passes forward, crosses the extensor carpi radialis and lies
just below the pronator profundus, or pronator longus, giving
branches to the skin. It passes downward on the radial side of the
ulnar and supplies the muscles of that part; it then continues
down the hand. Branches are given off to the extensor proprius
pollicis, the interosseous dorsalis, the flexor digitorum, and to the
skin between the thumb and the forefinger.

The intercostal nerves (Fig. 70, No. 18) are given off from the
spinal cord of the dorsal region. The superior branches are small
and supply the superior dorsal region. The inferior branches lie
one behind each rib, innervate the intercostal muscles, and give
a few twigs to. the superficial thoracic muscles.

‘The Lumbo-sacral, or Crural, Nerve Plexus.—The crural plexus
(Fig. 70, No. 35 and 36) is made up-of trunks from the last two
lumbar and first four sacral spinal nerves. There are two portions
of. this plexus separated by a considerable distance.

The anterior portion (Fig. 70, No. 35) consists of the lumbar
nerves and a portion of the first sacral nerves. The fusion takes
place. on the bony ridge that separates the lumbar from the sacral
region.

The posterior portion (Fig. 70, No. 36) consists of a part of the
first sacral and all of the three succeeding nerves.

The anterior nerve of this plexus is distributed to the abdominal
muscles. An anterior branch is given off to the sartorius. A large
cutaneous branch enters between the sartorius and the ilio-trochan-
teric eminence, and supplies the outer and the upper surface of the
upper thigh region. Several short branches are given off from the
middle, or main, mass of the crural plexus to the ilio-trochanteric,
or gluteal, muscle. Another nerve passes over the side of the
sartorius adjacent to the femoro-tibialis, or extensor femoris,
and supplies the ilio-tibialis, or gluteus primus. The rest of this

286 ANATOMY OF THE DOMESTIC FOWL

section of the crural nerves pass in a distal direction over the inner
and front side of the cutaneous nerve and enter the ilio-femoralis,
or gluteus medius, the ambiens and the femoro-tibialis muscle.

The furcalis nerve comes out between- the lasttwo lumbo-sacral
vertebre.

The obturator nerve springs from several roots. The anterior root
of this nerve comes from the main trunk of the crural plexus, and
its last root from the furcalis nerve. The obturator nerve extends
in a ventral direction from the plexus, then horizontally on the inner
surface of the.abdominal cavity. It gives off twigs to the obturator
muscle and then passes through the obturator foramen. After leav-
ing the abdominal cavity it gives branches to the accessorius, the
obturator, and, the pubio-femoral,,or adductor longus muscle.

The crural plexus gives off another large nerve trunk which ex-
tends downward. Shortly after emerging from the plexus it gives
off a muscular branch to the ilio-femoralis, or gluteus medius
muscle. It then passes between this muscle and the shaft of the
femur, to the inner posterior surface of the thigh, and to the inner
surface of the knee. It gives off.a branch to the structures of the
knee. At the knee this nerve terminates in several branches, some.
of which pass to the inner surface of the tibial head, the internal
lateral ligament, the periosteum, the internal condyle, and finally
to the upper part of the head of the gastrocnemius muscle.

The main part of this nerve passes downward as the cutaneous
nerve, along the inner surface of the lower thigh.

The ischiadic plexus (Fig. 64, No. 41) has five to six roots, which
fuse into the ischiadic trunk. This main trunk extends out of the
abdominal cavity, through the ischiadic foramen, close behind the
anterior trochanter of the ilium (Fig. 65, No. 1). It gives a branch.
to the external ilio-femoral or gluteus medius, and a branch to the
post-acetabular portion of the ilio-tibialis, or gluteus primus
muscle. The main trunk (Fig. 69, No. 13) passes downward to the
lower portion of the thigh. In this course there are two branches
which run parallel to the femoral artery and the femoral vein. It
gives off a small muscular branch to the accessorius, and further
down gives off a long slender branch to the outside of the knee-
joint. It gives off a lateral cutaneous branch (Fig. 66, No. 7) to-
the posterior outer portion of the lower thigh. It supplies motor,
fibers to the external head of the gastrocnemius muscle.

At the knee region the ischiadica divides into three parts. The.

NEUROLOGY 287

largest branch (Fig. 69, No. 14) passes with the tendon of the ilio-
fibularis, or biceps femoris muscle, through a loop, the biceps band,
and lies on the upper lateral surface of the fibula. It is covered
by the external head of the gastrocnemius muscle. It innervates
the three posterior muscles of the lower thigh, and then divides into
two branches. One, the superficialis peroneus (Fig. 69, No. 16)
passes with the profundus nerve, forming a double trunk and’
occupying the tibio-fibular groove on the antero-lateral side. It
passes over the transverse ligament and the tibio-metatarsal joint,
and after sending small branches to the structures of the tibial
side of the metatarsus, it ends as a cutaneous nerve on the upper
side of the third and the fourth toe.

The other branch is the peroneus profundus, which separates from
the peroneus superficialis and passes downward in company with
the tendons, under the transverse ligament, and then along the
anterior upper surface of the metatarsus, where it innervates the
muscles of that region. It gives branches to the malleolus, to the
tendons of the third toe, and to the median part of the second toe,
and supplies the cutaneous structures of the third and the fourth toe.

The third branch of the ischiadica, a long nerve, is given off just
after the ischiadica passes through the loop. It passes downward
between the two peroneal nerves.’ It is covered by a sheath. It
passes over the posterior outside rim of the intertarsal joint and
innervates the tendon sheath. The main portion of this nerve is
located on the anterior surface of the tendon Achillis, and passes
down on the plantar ‘side, and innervates the periosteum and all
plantar foot muscles.. It finally radiates to the plantar surface of
the three anterior toes.

The integument of the toes is sparingly supplied with nerves.

The nerve trunks that do not pass through the biceps band, or
loop can be divided into a medial (Fig. 69, No. 15) and a lateral:
(Fig. 69, No. 17) portion. The medial portion (Fig. 69, No. 15)
soon divides into numerous branches which supply the muscles’
of the posterior and the inner portion of the thigh. A rather large,
long branch passes downward along the tendon of the plantar mus-
cle, which lies on the posterior median edge of the tibia, and gives
off twigs to the median and posterior part of the intertarsal joint, '
supplying the periosteum and other structures and the adjacent’
skin. It passes downward along the.outer side of the medial meta--
tarsal insertion of the tendon Achillis. ;

288 ANATOMY OF THE DOMESTIC FOWL

The fifth branch is given off from the second trunk and lies later-
ally. It is covered by the external head of the gastrocnemius,
passes along the vena saphena, and gives off a short main branch
to the inner side of the intertarsal joint. The main part passes
the tibial side of the joint, becomes subcutaneous, and finally
innervates the two plantar muscles. A lateral ascending inner
branch innervates the flexor perforatus digitorum, and, in company
with an outer branch, the external head of the gastrocnemius, and
also the flexor pedis perforatus.

The plexus pedundus is formed from the spinal nerves coming out
of the plexus ischiadicus. These fibers emerge caudalward and
are directed horizontally. They frequently anastomose with each
other, especially on the pubic rim and on the outside of the plexus
ischiadicus. These branches are deeply imbedded in the kidney
substance and innervate the pubio-coccygeus, or depressor coccygis
lateralis, the ilio-coccygeus, the transversalis, the sphincter, and
other muscles of this region, and the skin of the anal region.

THE BRAIN

The Brain Coverings.—The cerebro-spinal axis of birds is similar
to that of mammals. The meninges of the brain are three in number,
dura mater, arachnoid, and pia mater. The dura mater is the
thickest. It is constructed of white fibrous connective tissue, and
lines the cranial cavity. Thus it serves as an internal periosteum.
It is continuous with the spinal dura mater at the foramen magnum,
and is also prolonged as a sheath of the nerves. In birds of flight
where the air sacs and reservoirs are developed to the highest
state, Sappy finds that, “just as the medullary tissue is replaced by
air in the bones of birds, so might it be imagined that the sub-arach-
noid fluid is also replaced by air around the spinal cord,” and ob-
servations justify the correctness of this statement. The dura
mater measures exactly the volume of the marrow in birds; so that
there does not exist between the fibers and the nervous surface
any space for an accumulation of liquid. This anatomical fact is
sufficient to demonstrate the absence of subarachnoid fluid in the
bird. In denying the existence of this fluid, it ought to be added
that in this class of vertebrates, the spinal prolongation is covered
by a triple envelope; and that between the pia mater and the dura
mater is a thin transparent membrane, which is lubricated by a

NEUROLOGY 289

serous fluid. This fluid however does not collect; it only moistens
the arachnoid membrane.

The arachnoid is located between the dura mater above and the
pia mater below. The pia mater adheres closely to the nerve
tissue.

The falx cerebri exists in fowls and in turkeys. It has the form of
a segment of a circle, and extends from the middle of the interval
of the openings for the olfactory nerves to the tentorium cerebelli.
The falx cerebelliis absent. The tentorium is small and is sustained
by a bony plate, and there are in addition two folds, one on each
side, that separate the hemispheres from the tubercula quadrigemina.
Owing to the absence of the falx cerebelli, the meninges lie close
together. The falx cerebri is ossified in birds.

The Brain Structure.—The brain (Fig. 62, C and Fig. 75, A and
C) is made up of three principal parts: the cerebrum, the cere-
bellum and the medulla oblongata. In a fowl of medium size the
brain weighs about 150 grains.

The pons varolii is absent in birds. The crura cerebelli (Fig.
75, No. 9) are immediately connected with the corpora restiformia.
The lower face of the isthmus is convex posteriorly; in front, the
tubercula bigemina (Fig. 75, No. 4) are united to each other by a
comparatively large transverse cord, formed by the optic nerves
intercrossing in the median line. The superior face of the medulla
oblongata is depressed above to constitute a fourth ventricle; in
front of this ventricle are the tubercula bigemina, or optic lobes.
These two voluminous tubercles are separated from each other above,
where they embrace the cerebellum, and are salient on the sides of
the lower face. They are hollow internally, and communicate
with the aqueduct of Sylvius. The thalami optici are not well
developed.

A large transverse fissure divides the cerebrum from the cerebellum
(Fig. 75, No. 5). The optic chiasm (Fig. 75, No. 15) behind which
lies the hypophysis (Fig. 62, No. C, 20) covers the region of the middle
brain. The large transverse fissure is the dividing line between the
hemispheres and the optic lobes. If the hypophysis be removed
there will be observed a slit surrounded by gray matter which is
called the tuber cinereum et infundibulum (Fig. 75, No. 18).
On the pars commissuralis and the after brain there are visible the
roots of the fifth, the ninth, the tenth, and the twelfth pairs of
cranial nerves. Close beside the median furrow which extends to

19

290 ANATOMY OF THE DOMESTIC FOWL

the front part of the long furrow of the spinal cord there is observed
the third pair of cranial nerves, which have their origin in the middle
brain. The fourth pair of cranial nerves extend from the roof of the
middle brain on both sides. between the middle brain and the optic
lobes. These nerves finally emerge and become visible on the
ventral surface.

The sixth nerve is visible near the middle furrow and almost in
the middle of the pyramids, and near the roots of the fifth, the
seventh, the ninth, the tenth, and the twelfth pair of cranial nerves.

THE DIVISIONS OF THE BRAIN

{ Thalamus

Pineal body
Infundibulum
Hypophysis

Forebrain | Optic tract and chiasm
Cerebral hemispheres
Olfactory lobes

Third ventricle
Lateral ventricles
Peduncles of the cerebrum
Midbrain | Optic lobes 3
Aqueduct

Medulla oblongata
Hindbrain | Cerebellum

Fourth ventricle

The medulla oblongata (Fig. 62, No. C, 1; Fig. 75, A and C) termi-
nates anteriorly in the pars commissuralis and the pars peduncularis.
As the spinal cord approaches the head there is a gradual swelling,
or lateral thickening, which merges into the medulla oblongata.
The superior and the inferior surface of the medulla oblongata (Fig.
75,No.A,1 and C,17) are flattened. There isa shallowfurrowand a
slight swelling at the point where the hypoglossal nerve emerges.
The central canal of the spinal cord gradually comes closer to the
upper surface and communicates with the fourth ventricle, at which
point the posterior raphe is shortened and the sulcus longitudinalis
posterior becomes shallow. At the point where the central canal
terminates in the fourth ventricle there is a V-shaped point called
the calamus scriptorius (Fig. 75, No. 2). The fourth ventricle is
located on the upper wall of the medulla oblongata below the cere-
bellum, and is bounded laterally by the peduncles of the cerebellum.
It is marked posteriorly by the calamus scriptorius and anteriorly
by the valve of Vieussens.

NEUROLOGY 291

The valve of Vieussens is located at the posterior end of the aque-
duct of Sylvius. The posterior part of the fourth ventricle is marked
by grooves or furrows. Extending along the central part of the
floor of the fourth ventricle there is a sulcus, or groove, called the
sulcus centralis, which divides the superior pyramids. On the
median lateral sides there are two points of gray substance which
form the alz cineree. The roots of the pneumogastric, the glosso-
pharyngeal, and the spinal accessory may be traced to the ale
cinerez and the gray matter of the ridges of the medulla oblongata.
The sixth pair of the cranial nerves emerge from the medulla near
the sulcus centralis and to the side of the auditory nerve. Part
of the trigeminus emerges from the rim of the furrow next to the
ridge. At the outer border of the medulla are observed the thick
ends of the roots of the pneumogastric, the spinal accessory, the
glosso-pharyngeal, and the auditory facialis.

On both sides of the sulcus longitudinalis inferior are found the
inferior pyramids, or pyramidal columns. These pyramids become
expanded near the origin of the third pair of nerves and merge into
the cerebral peduncles, or crura cerebri.

The pyramidal fibers may also be traced to the optic lobes. The
roots of the abducens are found at a point between the crura cerebri
and the optic lobes. The third pair lies to the side of this, and the
roots of the trigeminus are adjacent to those of the third. A
bundle of fibers from this region pass into the cerebellum and form
the crura cerebelli; others pass into the cerebellum from the side,
spreading out in fan-shaped radiation, and forming the white central
substances peculiarly arranged, called the arbor vite, or tree of life.
A third bundle fuse with the crura cerebelli anteriorly, and pass
into the peduncles of the cerebrum, or crura cerebri.

The gray ganglionic substance forms columns which extend the
whole length of the medulla oblongata and into the cerebri. The
medulla oblongata contains numerous centers which preside over
various visceral functions as deglutition, respiration , thermotactic,
secretory, cardiac, and digestion.

In the medulla as in the spinal cord there are five main groups
of cells. First, the posterior or upper horns, from which come the
somatic sensory nerves. Second, Clark’s cells, located centrally,
which are the origin of the ganglionated splanchnic nerves. Third,
cell groups of the lateral horns which are the center for the non-
ganglionated splanchnic nerves, and certain other nerves for the

292 ANATOMY OF THE DOMESTIC FOWL

viscera, including the enteric muscles. Fourth, cell groups of the
anterior horns, which are the center of all somatic voluntary
muscles. Fifth, groups of single cells probably belonging to the

Fic. 77, A.

G, A section through the tuberculum bigeminum. 1, Pia mater. 2, Nerve

- fibers. 3, Fine granular ground substance. 4, Thin layer of small cells. 5,

Fine granular ground substance. 6, A second thin cell layer. 7, Fine granular

ground substance. 8, Third thin cell layer. 9, Fine granular ground substance.

10, Fourth widely extended cell layer. 11, A fine granular layer. 12, A thick

layer of spindle cells. 13, A layer of medullated nerve fibers. 14, Ependemal
cells. 15, The sinus.

H, A transverse section through the medulla oblongata. 1, 3, 4 and 6 are
ganglioniccenters. 2, Thedorsalgroove. 8, Theventral fissure. 5, Thecentral
canal. 7, Fiber tracts.

I, A transverse section through the cervical portion of the spinal cord. 1,
Ventral septum. «, Dorsal septum. 3, Thecentral canal. 4, The dorsal horn.
5, The ventral horn.

J, Asection through the wall of the oil gland, orrump gland. 1, The stroma.
z, The tubular glands some of which are branched.

K, Asection through a spike of acomb of acock. 1, Theepitheliallayer. 2,
A dense fibrous subepithelial layer. 3, A second fibrous vascular layer. 6, A
denser central core supporting the large arteries and veins. 4, A vein. 5, An
artery.

L, A section through a lobe of the wattle of a hen. 1, The epithelial layer.
2, Adense vascular layer. 3, Avein. 4,Anartery. 5, A loose fibrous vascular
structure.

posterior horns which are probably centers for other splanchnic
nerve fibers.

The gray matter in the cord is in the form of two commas placed
with their backs together with the central canal passing between

NEUROLOGY 293

them. The central canal is located in the center of the cord. As
the cord nears the medulla oblongata the form of the gray matter
changes. The second, the third, and the fifth ganglion centers are
arranged laterally, and show a distinct side-horn group. The
central canal separates the two Clark’s columns; later the side-horn
group enlarges and extends ventrally around the anterior horn group
and joins on the other side in half-moon shaped formation.

The central ganglionic mass of the spinal cord, the center for the
enteric visceral system, is divided into three complex parts. First,
there are cell groups on both sides of the posterior raphe. Second,
the half-moon shaped ventral groups extending parallel peripherally
described above. Third, lying between groups one and two a com-
plex group, which possesses a large collection of cells. These fur-
nish splanchnic nerve centers, the anterior supplying motor nerves
and carrying motor impulses outward, and the superior sensory
which carry impulses to the centers. The cell group of the superior
horns takes a sidewise peripheral position (Gadow).

The cerebellum (Fig. 62, C, 2) is located above the medulla oblon-
gata and posterior to the cerebrum. The cerebellum consists prin-
cipally of a median lobe called the worm. The lateral lobes are
conical and rudimentary. The under part of the worm forms the
roof of the fourth ventricle.

On the upper surface of the cerebellum are numerous transverse
markings (in the hen 13 or 14) which divide the lobe into leaves.
When the cerebellum is cut lengthwise there is observed on the
sectioned surface the peculiar arrangement of the white and the
gray matter, the arbor vite, mentioned above. There is a small
cavity in the cerebellum which communicates with the fourth
ventricle.

The cerebellar cortex shows four parts, namely: First, the central
part composed of white medullated fibers, between which are
arranged neuroglear cells. Second, a rather reddish layer of cells
of different sizes. These cells are embedded in a fine ground
substance and are about 0.003 mm. in diameter. Third, a plain
layer of large pear-shaped ganglion cells, the cells of Purkinje.
Fine branches extend outward from the apex of these cells. Fourth,
an outer gray layer which consists of small multipolar nerve cells
with some neuroglear cells. The color of these three layers, accord-
ing to Gadow, depends upon the color of the plumage; that is, if
the plumage is dark, this layer is dark; if light, the layers are

204 ANATOMY OF THE DOMESTIC FOWL

light. The marked coloring is said to be most distinct in the
second layer.

The anterior portion of the cerebellum consists of medullated
nerves whose fibers run crosswise. ‘These are the extensions of the
true cerebellar fibers, which become fewer and fewer as they proceed
anteriorly. Finally, a few remaining fibers running crosswise fuse
as the commissura Sylvii, and extend into the lobi optici. A layer
of nerve cells extends under these medullated nerve fibers.

A bundle of fibers extending from the medulla oblongata. These
fibers extend into the optic lobes, form the crura cerebri, or
peduncles of the cerebri, and also form the inferior wall, or floor,
of the aqueduct of Sylvius. The crura are sometimes spoken of as
the partes pedunculares. These contain gray matter. The follow-
ing division is made of the ganglion of this region. First, a group of
cells near the base of the peduncles, which are divided from the
ventral rim by the arciform fibers. This ganglionic formation may
be considered an extension from the medulla oblongata. Second,
a group of the ganglion cells of the lobus optici. Third, a group
of cells lying near the lobus opticus, which give rise to the ascending
roots of the trigeminus. Fourth, a group of ganglionic cells from
which spring the roots of the motores occuli, and which lies near
the middle line and under the sulcus centralis. Many ganglion
cells are found to the right and to the left of the sulcus centralis,
which show different arrangement of the cells at different levels.
Fifth, a group of irregular cells which extends centrally on the
superior walls of the third ventricle and to the superior part of the
lobus opticus.

The microscopic structure of the roof of the lobus opticus, or
corpus bigeminum, shows that the layers are arranged parallel to
the pia mater and are divided into the following parts:

Externally, the pia mater.

An outer layer of very fine nerve fibers, which lies just below the
pia mater.

A layer of fine granular ground substance.

A thin layer of small cells the diameter of each of which is 0.038
mm.

A layer of fine granular ground substance.

A second thin cell layer.

A zone of fine granular ground substance.

A third thin cell layer.

NEUROLOGY 295

A fine granular ground substance.

A fourth widely extended cell layer.

A fine granular layer.

A somewhat thick layer of spindle-shaped cells.

A layer of medullated nerve fibers.

This last is the inner layer of nerve fiber. On the inner surface
of this layer we find the ependymal cells, the cells that line the cavity
of the optic lobes. The commissura Sylvii form the covering of the
lobi optici and join these two lobes. This commissure is formed
from the upper and the lower layer of nerve fibers. In the commis-
sure these fibers cross each other.

The hypophysis (Fig. 62, No. C, 20) lies back of the chiasm, or
optic commissure, and below the middle of the third ventricle. The
infundibulum, a pedicle-like structure, connects the hypophysis with
the third ventricle of the cerebri. It contains a cavity and forms
an extension of the third ventricle. The hypophysis is divided into
two lobes, an anterior and a posterior. ;

The third ventricle communicates anteriorly with the lateral
ventricles of the cerebri through the foramen of Monro, and pos-
teriorly with the fourth ventricle through the aqueduct of Sylvius.
The posterior walls of the third ventricle are relatively thick and
form the posterior brain commissure. The wall is thin from the
commissure to the chiasm. Within it lie two ridges, which connect
the two hemispheres with the corpus callosum, and, farther ante-
riorly, with the anterior cerebral commissure. The space from
the third ventricle and to the anterior commissure is called the
lamine terminales.

The pineal gland, located between the cerebri and the cerebellum,
lies against the choroid plexus, which covers the highest point of
the third ventricle.

The cerebrum is divided by a deep longitudinal fissure into two
hemispheres. The cerebrum is shaped somewhat like the heart on
a playing card. The lower face is somewhat flattened. The upper
and lateral sides are not provided with convolutions or sulci, but
are smooth. The fissure of Sylvius is faintly marked on the inferior
face. The olfactory lobes appear well developed and are relatively
large for the size of the brain. They lie close together on the extreme
anterior portion in the median line. :

The olfactory cerebral crura emerge from the cranium at the
upper angle between the posterior wall, the roof, and the septum of

296 ANATOMY OF THE DOMESTIC FOWL

the orbit, and pass through the olfactory foramina and in grooves
on the upper part of the septum; then passing forward they pene-
trate the frontal structure and are finally distributed over the
turbinated mucous membrane.

The corpus striatum is large; it occupies nearly the entire floor
of the ventricles.

The anterior commissure is found between the hemispheres. Its
middle part lies in the lamina terminalis on the division between
the anterior and the middle brain, and close to the thalami optici.
Its side extensions are rounded masses called the nervi amygdales.

The corpus callosum, quite rudimentary, lies on the posterior
dorsal rim of the anterior commissure.

The corpus striatum forms a thin broad ridge, which passes ven-
trally. This structure consists of twenty-five large pyramidal cells
which lie in the posterior lateral dorsal section, and of from ten to
fifteen pyramidal cells which are located in the rest of the section.
In addition to these two groups there are many cells about 5 milli-
meters in diameter. These lie, six or more, in a nest imbedded in
neuroglia. There is a thin layer of spindle cells near the ventral line.
The outer nerve nest, or nerves amygdalis, lies in the’ posterior
lateral ventral part. It is covered by a thin membranous layer.
Its cells are pyramidal in shape and are from ro to 15 millimeters in
diameter. The cells terminate in spindle form toward the periphery.
Nerve fibers extend from the anterior commissure.

The outer wall of the corpus striatum consists of the following
layers:

An outer white layer consisting of fine medullated nerve fibers
imbedded in a ground substance containing numerous nerve cells.

A layer of ganglionic cells, consisting of pyramidal cells from 10
to 15 millimeters in diameter, of other round cells 20 millimeters in
diameter, and finally of cells only 5 millimeters in diameter. This
layer forms a reddish line in the dorsal portion of the corpus striatum.

These layers form part of the median and the posterior cerebral
wall of the lateral ventricle. The lateral ventricle is closed except
for a slit-like opening behind the posterior commissure. This is the
foramen of Monro, through which the lateral ventricle communi-
cates with the middle, or third, ventricle.

The choroid plexus is found at the base of the lateral ventricle.

The wall of the lateral ventricle becomes thinner near the region
of the transverse commissure on the surface toward the middle

NEUROLOGY 207

brain. At this point the pia mater and the ependyma, or the lining
cells of the ventricular membrane, form the major part of the wall. —

The domestic fowl does not have the hippocampus.

The wall of the middle ventricle consists of an outer white layer,
which is arranged similarly to that of the corpus striatum. The
ventral rim of the wall is formed by a spiral band which consists
of fine medullated fibers, in which are imbedded a few cells.

The processus cerebri mammillares are also called the tubercula
olfactoria. From these structures extend forward the olfactory
nerves, the posterior roots of which may be traced to the walls of
the lateral ventricles.

The structure of the processus cerebri mammillaris is made up of
five layers as follows:

An outer layer, which consists of colorless olfactory fibers extend-
ing in all directions. :

A granular ground substance layer, in which are imbedded a few
cells.

A thicker granular layer, on the inner edge of which are twenty
large pyramidal cells with processes pointing outward.

A layer of closely packed cells, in which are fine medullated nerve
fibers. These cells are about 5 millimeters in diameter.

An innermost layer of ependymal cells.

Near the hemisphere the peripheral nerve fibers and nerve cells
disappear, leaving only the ground substance of the processus to aid
in the formation of the hemisphere.

There is a long bundle of fibers on the lower surface of the hemi-
sphere, which blends with the substance of the olfactory fibers.

The peduncles of the cerebrum (Fig. 62, No. 21) are the slightly
diverging columns of nerve tissue, which form the anterior continua-
tion of the medulla oblongata and disappear under the optic tracts
and the chiasm.

THE SYMPATHETIC NERVOUS SYSTEM

The sympathetic nervous system commences anteriorly at the
large superior cervical nerve ganglion. This ganglion, anteriorly,
brings into communication the glosso-pharyngeal, the pneumo-
gastric, or vagus, and the sympathetic system. ~

The following nerve trunks emerge from the superior cervical:
nerve ganglion: a large trunk fusing with the vagus and directed

208 ANATOMY OF THE DOMESTIC FOWL

downward, accompanying and surrounding the carotid artery; a
second large trunk fusing with the recurrent pharyngeus and the
glosso-pharyngeus; a third trunk which merges with the hypoglossal;
finally several trunks which are distributed to the head.

The temporo-lacrimalis, one of the large sympathetic nerves of
the head, as it extends from the cervical nerve ganglion, receives
branches from the ganglion radicis vagi. This nerve, passing be-
tween these two ganglions, extends horizontally forward and out-
ward through a foramen, crossing the glosso-pharyngeus. Near
the Fallopian canals it crosses the facial nerves, lies supero-laterally,
and receives a short branch from the facial nerve whose fibers are
traceable to the geniculate ganglion. It also receives a branch
from the recurrent maxillaris.

This nerve accompanies the external ophthalmic artery forming
around it a network of fibers, called the external ophthalmic plexus.
It lies outside and downward from the optic-nerve, sends fine
branches to the external ophthalmic artery and to the masseter
artery, and extends along with a small branch of the superior
maxillary nerve to the skin of the outside rim of the eye cavity.

The ophthalmic plexus, a second trunk extending to the head,
enters in its course, anteriorly, the lacrimal plexus. Its fibers also
supply the lacrimal gland, and finally anastomose with the second
recurrent branch of the trigeminus.

The sympathetic caroticus cephalicus nerve, a third trunk extend-
ing to the head, after emerging from the large superior cervical nerve
ganglion, receives some small branches from the glosso-pharyngeal
ganglion, and then enters, in a horizontal manner, a foramen, the
canalis caroticus externus, located in the lower part of the basi-
occipital and the sphenoid bone. The anterior opening of this fora-
men, or canal, is close to the posterior part of the pterygoid bone.
Inside this canal the sympathetic caroticus cephalicus receives a
small branch which extends in a straight line from the basal part of
the facial nerve. After receiving this branch, the nerve trunk, pass-
ing to the ear drum, lies close to the petrosum and the sphenoid. It
is covered by the masseter muscle. The carotic ganglion is located
at the point of the fusion of the caroticus cephalicus with the main
trunk. At this point the caroticus cephalicus divides into two
branches. The first is the superior recurrent nerve, which lies
close to the upper surface of the ale of the sphenoid, passes between
the obliquus externus and the orbital wall, around the eyeball,

NEUROLOGY 299

and finally into the orbital septum and the internal muscles of
the eye. It communicates with the ophthalmic nerve and sends
twigs to the lacrimal gland, the gland of Harder, the upper eyelid,
and the nose. The orbito-nasale ganglion is located where these
nerves communicate near the nasal region. The second branch of
the sympathetic caroticus cephalicus is the inferior recurrent nerve.
This branch passes forward and dorsally from the pterygoid bone to
a point where the upper rim of the rising wings of the jaw bone meets
the sphenoid rostrum. In this course, some branches are given
off to the pharynx, one branch near the lacrimal gland, and a branch
which communicates with the superior maxillary nerve just before
the nerve enters the jaw bone. The spheno-palatine ganglion is at
the point of fusion.

The terminal branches of the spheno-palatine are distributed
to the hard palate, the nose, and the lacrimal gland.

From the large cervical nerve ganglion and near the roots of the
caroticus cephalicus are given off a few small nerve fibers which pass
alone to the pharynx or accompany the jugular nerve branches, and
fuse with the main trunk of the caroticus cephalicus nerve.

From the large superior cervical nerve ganglion the sympathetic
trunk, extends downward toward the thorax.. It is covered deeply
with muscles. This portion is known as the cervical sympathetic
nerve trunk. A trunk lies on each side of the cervical vertebre.
The large thoracic nerve ganglion, the inferior cervical, is located
along this trunk at the entrance of the thorax. From this ganglion
there is given off the recurrent cardiacus which supplies the heart.
The end branches of the sympathetic nerve trunk blend with the
pneumogastric nerve. The inferior nerve ganglion is the ganglion
cardiacum. Near this ganglion is found a nerve plexus in which
there are imbedded peripherlistic ganglia. This thoracic plexus,
accompanying the collica artery, passes to the abdominal region,
supplying the intestines and taking part in the formation of the
abdominal plexus. The abdominal plexus is located near the
anterior portion of the kidneys. Its fibers are directed mainly
downward to the visceral organs. The large intestine, the rectum
and the copulatory organs receive branches. These latter branches
take part in the formation of the pedunda nerve plexus. Some
branches of this plexus, follow the branches of the posterior mesen-
teric artery.

The thoracic trunk (Fig. 64, No. 42) of the sympathetic is double.

300 ANATOMY OF THE DOMESTIC FOWL

The anterior portion gives off an anterior splanchnic nerve, or
plexus (Fig. 64, No. 43) which accompanies the celiac axial artery
to the gizzard and liver, communicating with the pneumogastric.
The posterior splanchnic nerve is intimately combined with the
adrenal body, and the testes, or the ovary (Fig. 64, No. 45). Intes-
tinal branches accompany those of the mesenteric arteries (Fig. 64,
No. 46). Other branches supply the kidneys, and communicate
with long branches of the spinal nerves destined for the cloaca and
adjacent parts, and thus form a plexus similar to that found in
mammals.

FUNCTIONS OF THE NERVOUS SYSTEM

According to function, the nerves composing the trunks are
divided into afferent and efferent.

The afferent nerves are those that convey the impulses from the
periphery of the body to the nerve center, which are located in the
brain or in the spinal cord. The impulses conveyed are those of
special senses, as sight, hearing, taste, touch, and smell. Impulses
producing sensation pleasurable or painful come from the skin, the
muscle, or the viscera.

The efferent nerves are those which convey impulses from the
nerve centers to the periphery. These impulses may be motor as
those going to the muscle ‘cells of the skeletal muscles, the viscera,
or the blood-vessels. These motor impulses make movements in
these organs possible. In the blood-vessel they result in the control
of the caliber of the vessel. These impulses may be of an inhibitory
character, as in slowing the heart. They may be secretory impulses
stimulating the gland to activity or regulating metabolism.

The ganglia are nerve centers which receive and generate im-
pulses; the nerve trunks are filaments which convey impulses. The
gray matter of the cord described above is the ganglionic portion,
and the outer white matter is made up of nerve fibers which convey
impulses from one part of the cord to another, or to and from the
brain.

The nerves that have their roots in the spinal cord superiorly,
are sensory; that is, they convey the sensory impulses from the
periphery to the cord ganglion and to the brain. They have a
ganglion just outside the cord.

The nerves that have their roots in the spinal cord inferiorly;
that is, they convey motor impulses from the nerve centers to the

NEUROLOGY 301

periphery. The function of the inferior roots is to supply all the
voluntary muscles as well as the oviduct, the intestines, and other
hollow viscera, including the blood-vessels with the power of move-
ment. Many of these fibers pass to the sympathetic ganglion and
are distributed as sympathetic nerve fibers.

The cord is divided into different tracts, that is, certain groups
of fibers convey certain kinds of impulses.

The superior column of the cord conveys to the cerebrum such
impressions as temperature, pressure, and muscular tension.

The fibers of the lateral columns carry sensations of pain.

The fibers of the direct cerebellar tract carry impulses which
result in the maintenance of the equilibrium of the body.

All the voluntary impulses originate in the.cerebrum, pass through
the cerebellum and travel direct to the bulb; they then pass over
to the opposite side, and travel by the crossed pyramidal tract to
the multipolar cells of the inferior horn of the spinal cord, and trans-
mit the impulse through motor fibers that originate at that point in
the cord.

All sensory impulses enter the brain on the side opposite their
origin, and all motor impulses leave the brain on the side opposite
that to which they are distributed. Injury of the motor area of the
right side of the brain leads to paralysis of the left side of the body.

An impulse of the vasomotor nerve travels in the lateral column
of the cord.

A nerve impulse may originate in the brain and be modified in
passing through a ganglion in the spinal cord or in the sympathetic
system.

The system of reflex action is as follows: first, an efferent nerve
which conveys the impulse from the periphery to a nerve center;
second, a ganglion, or nerve center, to receive the impulse and gen-
erate other impulses; third, an efferent nerve to convey the impulse
from the nerve center to the periphery.

The following is an example of reflex action. The foot of a fowl
is pierced with a pin. The sensory impulse is conveyed by sensory
nerve fibers to the nerve centers. In this center the ganglionic
nerve cells generate a motor impulse which is sent back through the
motor nerve fiber to the muscles controlling the part. The result
is that the muscle contracts and jerks the foot.

There are many functional centers located in the medulla oblon-
gata. Destruction of this part of the system results in instant death

302 ANATOMY OF THE DOMESTIC FOWL

of the bird. In addition to furnishing a path for fibers carrying
impulses from the body to the cerebrum, it furnishes a large number
of centers for such functions as respiration, swallowing, secretion,
temperature, and vasomotor and cardiac activity. .

The function of the cerebellum is principally that of coérdination.
It brings about harmony and rhythm in muscular movements. If
the cerebellum be removed, the bird can no longer walk. It has
lost, with this removal, all power to codrdinate.

The cerebrum of the bird has no convolutions, and the gray, or
ganglionic, portion is thin, indicating low power of intelligence.
There are certain areas presiding over other functions, as motor
areas, sensory areas, and so on.

A careful study of the brain of the fowl shows us that the centers
presiding over sight and smell are well developed.

The olfactory bulbs are the centers of the sense of smell.

The optic thalamus is the center of the sense of sight.

The sympathetic nerve system transmits impulses to the invol-
untary muscular structure of all organs, including those of the
intestinal tract, the blood-vessels, and perhaps also the glands.

ESTHESIOLOGY
THE SENSE ORGANS

The five special senses are seeing, smelling, tasting, hearing, and
feeling.

THE ORGAN OF SIGHT

The sense of sight in the bird is well developed. The eye (Fig. 26,
D, E and F), the organ of sight, is relatively large, round laterally,
and rather flattened antero-posteriorly. It is located at the side of
the head. The eyeball is only slightly movable. The septum
interorbital separates the two eyeballs laterally. As in mammals,
the eyeball has three coats, which are from inside to outside, the
retina, the choroid, and the sclera. The sclerotic coat is completed
anteriorly by the cornea with which it forms a union called the
corneo-scleral juncture. Around the cornea the sclerotic coat con-
tains a ring of osseous scales varying in number from twelve to
twenty. The sclera may become ossified posteriorly, forming an
osseous sheath around the optic nerve. The pecten is a vascular
comb-like membrane stretching from the nervous opticus to the
crystalline lens. The choroid coat is always black. The pupil in
the hen is also black and round. The iris contains striated muscular
fibers. The membrana nictitans, located at the inner angle is well
developed. It is moved by two muscles (Fig. 26, No. B, 7, 8, 10).
The lacrimal gland and the gland of Harder are present. There is
no mebomian gland. :

The fears are secreted by the lacrimal gland and are drained away
from the fore part of the eyeball by two small canals which extend
into a lacrimal sac. From this sac there extends a tube into the
nasal cavity called the lacrimal duct.

The lower lid is the larger and often incloses a small cartilaginous
plate. The conjunctiva is a true mucous membrane which covers
the anterior portion of the eye cavity attaching to the cornea-
scleral juncture.

The choroidea is rich in pigment. On its inner surface lies the
dark pigment layer of the retina. The corpus ciliare, that part of

393

304 ANATOMY OF THE DOMESTIC FOWL

the choroid coat bearing the ciliary processes, consist of numerous
folds. The ciliary muscles are arranged obliquely. 'Each consists
of three digitations.

The iris is covered on the posterior side with pigment, the color
of which determines the color of the eye. The yellow pigment of
the iris has been said to be due to carotin and zanthophyll and the
black pigment to melanin. The enlarging and the contracting of
the pupil is brought about by muscles. The reduction of the
pupillary caliber is due to the sphincter pupillary muscle. It is
said by some anatomists that the muscles controlling the caliber of
the pupil in the bird furnish voluntary motion and that the capability
of accommodation of the eyes is greater in birds than in mammals.

The retina contains no blood-vessels; otherwise the structure is
similar to that of mammals. The crystalline lens is flattened on the
corneal side and is convex posteriorly. The lens epithelium de-
velops into fibers in the parts close to the equator, and are almost
perpendicular to the eye axis. The corneal portion is relatively
small.

The sclerotic coat is dense and white. It is divided into three
layers. It is thin and flexible, and somewhat elastic posteriorly.
It has an internal layer of hyaline cartilage. Anteriorly its form
is maintained’ by the circle of osseous plates mentioned above.
These plates, interposed between the exterior and the middle layer,
are located immediately behind the cornea. The scales are thin
and of oblong quadrate shape, being elongated from: before
backward.

The choroid coat is a membrane loosely cellular and highly
vascular. It is impregnated by a black pigment. Opposite the
bony circle the choroid separates into two layers. The external
layer is the thinner and adheres at first firmly to the sclerotic; it
passes forward to become continuous with the iris. The inner layer
is thicker than the external. The two layers are made up of radiat-
ing fibers which terminate anteriorly in the ciliary processes, the
ends of which are adherent to the capsule of the crystalline lens.

The iris is delicate in structure. It is composed of a fine network
of interlacing fibers.

The ciliary nerves and blood-vessels run in the form of single
trunks between the choroid and the sclerotic, and terminate ante-
riorly in a ring-shaped plexus for the supply of the iris and the
muscular circle of the cornea. As stated before, the pupil in the

ESTHESIOLOGY 305

fowl is round, but in the goose it is elongate transversely; and in
the owl, a vertical oval.

The optic nerve approaching the sclerotic coat becomes altered
into a conical extremity, which enters a sheath and is directed down-
ward and obliquely forward. The extremity of the optic nerve in
the interior of the eye presents a white narrow streak. Branches of
the opthalmic artery enter the eye between the lamina of the retina,
along the whole extent of the oblique slit, and penetrate the fold of
the pecten upon which they form a delicate ramification.

The crystalline lens is of soft texture. It is inclosed in a capsule
and is nearly round. It adheres very firmly in the depression in the
anterior part of the vitreous humor. The capsule is lodged between
two layers of hyaloidea, which as they recede from each other, leave
around its circumference the sacculated canal of Petit.

The cornea is of horny consistency and is transparent. Light
thus rapidly passes through it to the posterior part of the eye.

The vitreous chamber, lying back of the crystalline lens, contains
a clear jelly-like substance.

THE ORGAN OF HEARING

The ear, the organ of hearing, has in the fowl no conchal cartilage.
The external auditory meatus, or canal opening, is found on each
side of the head, and is usually guarded by a few stiff, short feathers.
In some kinds of birds these feathers are capable of being erected
so as to direct the waves of sound into the inner ear. The outer
entrance of the ear contains glands.” This canal isshort. It leads
to the drum, which is somewhat convex from the outside, and which
has a membrane forming a complete curtain stretched over the
outer part. The irregularly formed drum has connection with the
air-containing cavity of the skull, and by a thin cartilaginous canal,
the Eustachian tube, with the pharynx. The auditory ossicles are
represented by only a single bone, called the columella, which
most closely represents the stapes of mammals. This is attached
by processes of cartilage to the tympanic membrane. Owen con-
siders these cartilages as representing the malleus of mammals.
Huxley on the other hand considers them to represent the incus.
Originating from the processes is a small muscle whichis attached
to the drum. This is by Shufeldt considered the Tensor tympani.
The drum cavity through the fenestra vestibularis and cochlearis

is connected with the labyrinth.
20

306 ANATOMY OF THE DOMESTIC FOWL

The inner ear consists of a membranous labyrinth, surrounded by
a spongy bony structure—the bony labyrinth. In it are recognized
the vestibulum, the three half-circle shaped canals, and the cochlea.
The superior semicircular canal is the largest. The acoustic nerve
enters at the end of the canals near the ampulle. The nerves are
supported in delicate vascular membranes lining the canals and
slightly projecting into the ampulle.

The vestibulum is a small irregular cavity which communicates
with the arcades and the cochlea, and through the fenestra vesti-
bularis with the drum cavity. The endolymph of the vestibulum
contains microscopic crystals of calcium carbonate. The semi-

Fic. 78——Diagram of the inner ear. 1, The integument. 2, The superior
semicircular canal. 3, The external canal. 4, The horizontal canal. 5, The
ampulla. 6, The obtuse osseous conical cochlear.cavity. 7, The Eustachian
tube. 8, The tympanum. o9, Filaments of the auditory nerve.

circular canals are relatively larger and thicker than in mammals.
The ampulle in the upper and back part are separated by walls.
The cochlea is an obtuse conical tube-like structure slightly curved
at the blind extremity with the concavity directed backward. It
contains a membranous lining. At this point the cochlea is broad-
ened and accommodates a branch of the auditory nerve. This
nerve spreads out in fine filaments upon the surface of the tubes.
The hollow space of the cochlea is divided by a spiral partition,
making two chambers, the scala vestibuli and the scala tympani.
These walls extend from the beginning of the cochlea.

The tympanic cavity is formed by the occipital, the basi- and ali-
sphenoids, the petrosal portion of the temporal bone. It represents
the stapedial canal leading to the foramen ovalis and the pneumatic

' ESTHESIOLOGY 307

apertures by which the air from the Eustachian tube is conducted to
the precranial diploz.

THE ORGAN OF SMELL

The nose is the seat of the peripheral portion of the organ of the
sense of smell. The terminals of the olfactory nerves, which receive
the impressions of odors, are broadened in the mucous membrane of
the walls of the anterior nares. There are no ethmoidal volutes, or
sieve-like structure, in birds. The nerve extends from the anterior
portion of the brain in cone-shape, finally dividing into filaments
which are distributed over the mucous surface of the turbinated
bones.

THE ORGAN OF TASTE

The most important part of the organ of taste is the tongue.
In birds the dorsum of the tongue is covered by a thick stratum
corneum, a heavy layer of stratified squamous epithelium. The
tongue, therefore is not in birds so well adapted for the perception
of taste as it isin mammals. The lingual branch of the trigemini
is lacking in birds. This fact makes the ninth pair, or the nervi
glosso-pharyngei, the exclusive nerves of taste. There is an opinion
ventured by one anatomist that, since the first and the second branch
of the fifth pair, or trigemini, have terminal filaments in the hard
palate, they may furnish fibers for the sense of taste. There are
many taste cells on the tongue and on the dorsal palate.

THE ORGAN OF TOUCH

The peripheral parts of the organ of touch in the fowl are the skin
and the feathers.

In a few birds special touch and taste perception can be supplied
by the edge and point of the beak.

In the skin of birds are found numerous sensory nerve endings for
tactile sense.

The sensory nerves, which provide the sense of touch, usually
terminate in one of two forms. The first are the Herbst’s bodies,
which in many respects are similar to the Picinian bodies.

Herbst’s touch corpuscles are found on all parts of the skin; they
are especially numerous in the region of the tail and of the wing. In
the wing they are particularly numerous in the region of the flight

308 ANATOMY OF THE DOMESTIC FOWL

feathers. They occur in large numbers in the periosteum of the
anterior tibial region and in the mucous membrane of the cloaca and
of the generative organs. They are numerous in the conjunctiva
and on the surface of the tongue. They are also found in the gums
and in the beak.

Herbst’s corpuscle is made up of a central fiber-shaped part with
a smooth extension of the axis cylinder of its nerve (Fig. 29, G).
This central fiber is surrounded by a peculiar protoplasmic body.
Outside of this there is a double row of cubical cells which surround
the axial part. These are close together. Outside of these there
occurs a concentric lamellar layer, which contains cells. In the
periphery these lamellae become more distinct and contain larger
but fewer cells. The capsule is made up of very thin layers, which
are continued into the périneural layer. Each body contains a
thin outer zone. The nerve fiber passes in a regular manner from
the axis cylinder, the myelemma, and the sheath of Schwann, and
as a delicate nerve twig is surrounded by a sheath consisting of
several perineural layers. As it enters the center of the touch cor-
puscle, it loses its myeline sheath near the base of the body, and the
terminal fiber becomes flattened. Its rim is directed toward the
two rows of cubical cells, and it ends in a rounded knob.

The touch corpuscles are the largest in the mucous membrane of
the cloaca and smallest in the skin. Hess has found these touch
corpuscles in the large filiform papilla on the side of the tongue
and a few on its lower surface. They are also found in the soft skin
of the edges and inner borders of the beak.

STRUCTURE OF APPENDAGES

The skin of the fowl is very thin and does not contain oil glands or
sweat glands. In the fowl the oil is supplied by a tail or rump gland,
the glandula uropygii (Fig. 35, No. 16). This gland is round or oval
in shape, and about the size of a pea and consists of two lobes. It
is of the tubular variety with a teat, which, in most instances has two
openings. A medium septum divides the gland into two halves.
The oil secreted by the columnar epithelial cells is collected in a
body cavity located in the center of the gland; this has a duct extend-
ing to the surface. The bird by squeezing out a quantity of this
oil into its beak oils the feathers, passing the beak over them, one
by one. The oil renders the feathers practically impervious to
water. It is necessary for the bird to give proper attention to its
plumage in order that the feathers appearin primecondition. Should
there be a disease of the oil gland, or should the bird become ill and
neglect its toilet the result is an unkempt appearance of the plumage,
the feathers becoming rather rough and more or less injured by the
weather.

The subcutis is well developed and furnishes to the cutis great
capability for movement, which is necessary for the rising and fall-
ing of the feathers. The corneum is very thin. Papillary bodies
are present only in a very few places, such as the region about the
eye and on the toes. Where the toes touch the ground in walking
there are large wart-like thickenings of the epithelium. Jn most
birds the shanks are unfeathered. The epidermis on the feathered
parts of the skin is thin, dry on the surface, and abounds in continu-
ous scales. The stratum corneum is very thick on the horny sheath
of the beak, on the top of the toes, on the spurs of the cock, and
on the scale plates that cover the skin on the shanks. The feathers
of birds serve the same protective purpose as hair on mammals.
In cold weather the skin muscles controlling the feather movements
contract; thus the feathers become ruffled much as we observe the
hair standing erect on horses under similar conditions. By increas-
ing the dead air space around the body, the radiation of heat is re-
tarded, and thé body kept warmer. The corneum of the skin is not

309

310 ANATOMY OF THE DOMESTIC FOWL

usually rich in blood-vessels; however, in the domestic fowls there
is in the comb, in the wattles, and similar appendages of the head, a
thick vascular network.

The beak and the claws are modified skin; they are true horn mate-
rial. At the base of the beak there is often formed scales, which
surround the nostrils, in whole or in part, and have a naked, or
waxy, appearance, which is known as the cera.

Fic. 79.—Photomicrograph of the section of skin from the sole of the foot of
a hen. 1, Horny stratified squamous epithelium. e@, Stratum corneum. |,
Stratum lucidum. c, Stratum germinativum. 2; Connective tissue supporting
membrane, pars reticularis. 3, Blood-vessels.

The feathers may be considered of two chief kinds, the quill
feathers and the clothing feathers. The most rudimentary of the
latter are known as down. A quill feather consists of two principal
parts: the quill, or calamus, and the vane, or vexillum. The quill
is continuous with the central shaft, called the rachis, the two form-
ing the stem of the feather. Projecting outward from the stem on
each side are a large number of pointed and very flexible barbs.
These barbs are located nearly at right angles to the quill and have
extending from them at right angles smaller processes or barbules.

STRUCTURE OF APPENDAGES 311

These barbules hook together the barbs and give the web its form.
In some feathers, as the hackle, and in the wing bar feathers of the
male of some breeds, there is a portion of the upper outer edge of the
feather not provided with barbules, which fact gives the feather its
characteristic appearance. The down feathers are loose and fluffy.
In this kind of feather the shaft is weak, and the barbs are not
provided with barbules. The barbs like the shaft may be considered
weak. These feathers give great warmth to the body. There are
fiber feathers appearing as hair-like filaments, and called filo-plume.
These are found scattered over the body; they are particularly abun-
dant in the region of the head and the neck.

At each end of the quill is a small opening, or umbilicus. Inside
the barrel of the feather there is pulp, which in young feathers is
very vascular; the vessels entering by the proximal umbilicus are
buried, along with part of the quill, in a papillated follicle of the
skin. From this follicle the feather is developed. At the base of
the shaft a secondary rudimentary quill is usually formed, which
may be represented by a mere tuft of down. On the same general
principle the smaller feathers are constructed. These cover the
body, the upper parts of the legs, and the head, while the larger
feathers and quills are confined to the wings and the tail. The
longest quill feathers are those arising from the hand, called the
primaries. Those arising from the forearm are called the second-
aries. Those that are developed from the proximal part of the arm
are called the ¢ertiaries. The rudimentary pollux carries some feath-
ers which form the alula, or bastard wing. The scapularies are
feathers covering the scapula and the humerus. Covering the
bases of the larger flight feathers are wing coverts consisting of
several rows of small feathers. The quill feathers of the tail are
called the rectrices. The rectrices have considerable mobility; their
bases are covered by a row of tail coverts.

The pedal digits of the natatores are joined by a membrane,
covered with scaly skin, which forms the web foot.

The feathers in many parts of the body are developed in rows,
there being intervals, or elongated skin areas, between these groups
of several rows, which are not provided with feather papilla, but
which are covered over by the feathers developed in front of these
spaces. The definite feather lines, or areas, have been called
pteryle. The intervening tracts devoid of feathers are called the
apteria.

312 ANATOMY OF THE DOMESTIC FOWL

The first outer covering of the bird, or baby chick, is a temporary
one consisting of fasciculi of long filaments of down. These
fasciculi on their first appearance, are enveloped in a sheath, which
soon becomes ruptured and are entirely cast off by the time the
baby chicks are ready to be taken from the nest or the incubator.

=

Fic. 80.—Photomicrograph of the skin of the neck of a S. C. White Leghorn
hen. 1, The skin possessing an outer stratum, the stratum corneum, next the
stratum lucidum, next the stratum granulosum and underneath the stratum
germinativum. Beneath the outer dark band representing the upper skin
strata is the pars reticularis of the derma. 2, Papilla showing from inside to
outside the hyaline feather wall, the stratum corneum, the Malpighian layer of
the follicle, the corium. Inside the feather is noted the pulp-like material.

The down fasciculi, each emerging from its small quill, are
succeeded by the feathers, which they apparently guide through the
skin.

Feathers do not spring from all parts of the body alike; especially
devoid of feathers are those parts where chafing and friction is
greatest, as under the wings and in the groin.

At the end of the quill there is a small opening, the inferior
umbilicus, into which projects a. papilla of the dermis. Where the

STRUCTURE OF APPENDAGES 313

quill emerges from the skin there is another small opening, the
superior umbilicus, from which springs frequently a small feather
called the kyporachis. The shaft, or rachis, has a groove extending
along that surface which lies next the body.

In the newly formed chick the first indication of feathers is the
formation of papille, which is constituted by the upward growth of
the dermis, or the sensitive and vascular parts of the skin. Then
the skin immediately around the papilla sinks downward, so that
later the papilla is inclosed in a follicle of the skin. The epidermis
over the papilla is the same as over the rest of the surface. The
horny outer layer of the epidermis forms for the growing feather a
protective sheath which is cast off as the feather is formed. The
feather proper develops from the underlying germinative layer,
which as the feather develops, forms a cylinder of cells. The lower
part of the cylinder is in touch with the papilla; this later becomes
the quill (Fig. 80, No. 2). The upper part of the cylinder develops
the web portion of the feather. As soon as the feather is fully
developed the papilla, which has projected into the quill and
nourished it, is withdrawn, and the quill becomes filled with a pith-
like material forming septa, which extend in different directions.

Once a year, usually in the late summer or in the fall, the entire
feather coat is changed. This process is called molting. During
this time the bird appears in a somewhat depressed condition, the
hen almost always ceases laying. Birds also molt in the spring,
to a limited extent. The male at this time takes on the so-called
breeding plumage, which is the most beautiful of the year. It has
recently been established by Rice, that the young fowl, in reaching
a stage of egg production, molts five times before the laying period
begins.

The structure of the skin of fowls is similar to that of the skin of
mammals. The skin consists of two layers the outer portion, or
epidermis, and the inner true skin, the cutis, corium, or dermis. If
we study a section of skin from the shank region of a fowl we find
the outer portion is differentiated into two distinct regions, the rete
Malpighii and the stratum corneum. The stratum corneum is the
outer horny layer. The cells making up this portion are fusiform,
flattened, and in regular rows. The nuclei in these layers of cells
are not pronouncedly visible, and the outline of the cells not clear
in a section such as used in our ordinary methods of study. The
corneum is a compact mass of remnant cells which have lost the

314 ANATOMY OF THE DOMESTIC FOWL

appearance and their texture of living cells. It thus becomes
modified into scales upon the skin surface.

. Between the stratum corneum and the stratum Malpighii there
is another zone which consists of the cells undergoing a transitional
stage from a cubical shape to a more flattened appearance, and
gradually becoming more granular and hyaline.

The various parts of the epidermis are in close genetic relation-
ship to one another. The upper layer of epithelium is constantly
being desquamated. This casting off is compensated for by a
continuous upward pushing of its lower elements. Cell prolifera-
tion occurs in the basal cells and in adjacent cellular strata of the
stratum germinativum, or stratum Malpighii, where the elements
are often seen in process of mitosis, or cell division. The young cells
are gradually pushed upward. During their course they assume the
general characteristics of the elements composing the layers through
which they pass. This process is as follows: each cell changes first
into a cell of the stratum Malpighii; then, when it commences the
formation of keratohyalin, it changes into a cell of the stratum
granulosum; later still, into a cell of the stratum lucidum; and finally
into an element of the stratum corneum, where it gradually loses
its nucleus, cornifies, and at last drops off.

The mesodermic portion of the skin consists of loose, subcutaneous
connective tissue containing some fat. The amount of adipose tissue
in the subcutaneous layer is subject to great variation; there are a
few places in which there is little or no fat. The upper portion
of this layer contains a few elastic fibers, which interlace and run
in all directions. Numerous round or oval cells are found in the
upper region. The lower and middle portions of the corium are
richly supplied with blood-vessels terminating into capillaries, which
penetrate the portions bordering the epidermis. Nerves giving off
terminal branches also occur.

The various colors of the skins of fowls are due to the distribution
of various quantities of two colors, orange-yellow and brownish-black.

The yellow pigment is probably carotin and xanthophyll, two
pigments contained in association with the chlorophyll of plants,
which the bird obtains in its feed. These coloring matters were
formerly called lipochrome; but as lipochrome may be any coloring
matter of fat, it is not sufficiently definite. This yellow pigment,
when present, is diffused through all parts of the cell. When dilute,
it gives a yellow hue; when concentrated, orange. It is found in the

STRUCTURE OF APPENDAGES 315

epidermis and in the fatty masses of and beneath the corium, and is
probably identical with the yellow color of fat in other portions of
the body and in the yolk of the egg. A yellow shank, in a heavily
laying hen, soon loses a part of its pigment; this is also noted of
the coloring matter in other parts of the body. This fact indicates
that the coloring matter of the fatty part of the egg yolk is from
the same source as that of the fat. The draught of this substance
is more than normally and the reserve is being drawn upon. Feed
rich in zanthophyll and carotin cause intense yellow colored yolks,
and feeds poor in these substances cause the yolks to be a pale
yellow. Cotton seed meal contains two pigments, one a yellow
crystalline substance and the other a brownish resinous substance.
Both of these pigments are probably deposited in the egg yolk. The
eggs of some hens contain a large quantity giving a light brownish-
yellow color to the yolk.

The brown or black-brown pigment is carried in microscopic
pigment granules, which may be scattered through the ordinary
cells or may be confined to special pigment cells. The former are
confined to the epidermis; the latter may be found in both layers,
but infrequently in the epidermis. When granules are present in
the flattened cells of the corium, they occupy the nuclear region.
They lie in short thin’lines while those of the under portion of the
Malpighian layer occur in oval groups. Where these granules occur
in the rete layer, they cluster around the nuclei. In the colored
skin there are dark pigment granules found in the corium and to a
less extent in the rete layer. Hanau has described a definite cellu-
lar body which he found densely packed among the black-brown
granules. There is a central body which sends out branches in all
directions. In very dark skinned shanks these ramifying strands
interlace, and form a compact network, which in many cases is so
thick as to give the impression of a homogeneous mass. Here and
there occur round or oval pigmented bodies, which Hanau concluded
were the star-shaped cells with their pseudopod-like appendages
contracted. Pigment cells commonly lie around blood-vessels, clearly
indicating their course. They frequently form a compact tube, but
more often are limited to fragments which only partly enclose the
vessels. Pigment cells occur in several well-defined localities: in the
upper portion of the cutis among the closely interwoven strands of
connective tissue; in the region bordering the blood-vessels; in prox-
imity to nerves, in nerve endings and in surrounding fat masses.

316 ANATOMY OF: THE DOMESTIC FOWL

Isolated granules are frequently scattered throughout the lower sec-
tion of the corium. Barrows concludes that the lower bodies of pig-
ment play little or no part in.the color of the external shank, as they
lie far below the opaque connective tissue. Melanin pigment gran-
ules are always contained in the pigment cells. When found in the
Malpighian layer, the pigment cells are of an oval form.

Immediately below the epidermis in the shank skin, extends a
space less in width than the row of columnar cells, which is devoid
of pigment. The brown pigment is melanin, which in large quanti-
ties takes on a black hue.

White skin does not contain superficial pigment. Melanin has
been observed in the study of white shank skin, but it lay at con-
siderable depth or in quantities insufficient to be noticeable. In
some breeds of fowls, as the Mottled Houdan, there are areas in
which much melanin is irregularly deposited, which circumstance
gives the leg its mottled appearance.

The yellow color is the result of a deposit of the yellow pigment
in the fat of the shank. This may be deposited in both layers of the
skin, or in the corium alone. When present it is diffused throughout
the entire cell as well as throughout the intercellular substance.
In young birds the Malpighian layer contains much yellow pigment.
Old hens have only small quantities in the corneum. In breeds
with normal yellow shanks old hens that have never laid eggs show
a deep orange color in both the dermis and epidermis.

In blue shanked birds melanin is present only in the corium. The
black pigment is seen through the semi-transparent Malpighian
stratum, making it appear bluish instead of brown or black.

The black shank color results when melanin appears in the epi-
dermis. Two forms of black pigment occur in the epidermis:
granules in both layers and pigment cells in the rete Malpighii.

The green shank is produced where there is pigment in the epi-
dermis and numerous melanin pigment cells in the upper corium.
It is an optical effect due to melanin lying under the semi-transparent
yellow epidermis. There is no melanin in the epidermis.

In the beak the corium of the skin is represented by a thin layer
located between the periosteum and the stratum Malpighii.
Numerous blood-vessels pass into it, and in the soft horn-like skin,
occur sensory nerve fibers.

The nails originate from the epidermis, of which they are a
modification. The nails of the toes are bent downward. They

STRUCTURE OF APPENDAGES 317

present a convex dorsal surface and are concave ventrally. The
dorsal surface consists of a horny plate, which is set in a nail matrix.
The ventral portion merges with the sides of the upper half, and,
as the lower portion is the softer and wears faster, the nail has a sharp
point and edge. The matrix is formed by a growth of the Malpigh-
ian layer of the cutis. A fold of skin lies over its posterior part.
The epidermic cells of the dorsal, or nail, part, and the base of the
ventral part grow fast. The outer cell layer gradually becomes
horn-like.

The spurs are conical with a flat base.. The basal part rests upon
an enlargement of the shank bone. Soft structure is found between
the horny spur and the bone. The upper cells, like those of the nails
and of the skin, are constantly being worn or cast off, and new cells
push up from the lower layers of cells. These newly formed
flattened cells soon become cornified. The oldest formation is
found at the tip and the youngest at the base.

EMBRYOLOGY OF THE CHICK

That a new individual may be brought into existence, there
must be accomplished the union of the male element, or spermatozoon,
with the female element, the ovum. This union is called fertilization.
In the fowl this fertilization is accomplished at the anterior portion
of the oviduct, after the calyx has ruptured and discharged its yolk,
and before the albumen has been formed: around it. The blasto-
derm is found on the surface of the yolk. One spermatozoon is all
that is required; in fact, only one can be used in this union.

Spermatogenesis.—The spermatozoa are formed by the seminifer-
ous tubules of the testis. From these cells, called the spermatogonia,
are formed other cells called spermatocytes, which in turn form the
spermatids, the immediate forerunners of the spermatozoa. During
the period of multiplication the spermatogonia divide repeatedly by
mitosis. Numbers of small cells are thus produced, each containing
in its nucleus the number of chromosomes typical of the somatic cell
of that fowl. In the second period the cells become larger and
spermatocytes of the first. order are formed. Then comes the
period of maturation, during which two succeeding divisions rapidly
occur. The first division results in the formation of two cells exactly
alike. These are spermatocytes of the second order. They differ
from the somatic cells in that they contain only one-half the typical
number of chromosomes. The second division produces two similar
spermatids from one spermatocyte of the second order. Therefore
four spermatids exactly alike may be formed from one spermatocyte
of the first order. From these spermatids the spermatozoa are
formed (Fig. 55). The heads of the spermatozoa contain the nuclei
derived from the spermatids; the necks contain the centrosomes; and
the tail, consisting of three parts is probably formed from the proto-
plasm. Three parts of the tail are as follows: first, the pars conjunc-
tionis, which unites the tail to the neck; second, the pars principalis,
which constitutes the main length of the tail; and, third, the pars
terminalis, which consists of an axial filament which transverses the
entire tail and ‘is surrounded by a protoplasmic sheath.

318

EMBRYOLOGY OF THE CHICK 319

Odgenesis.—The ovum during its formation passes through three
stages. i

The first stage, that of division, takes place before the chick is
hatched, and, according to Bradley, comes to an end about the time
of hatching. This stage consists of the rapid formation of ova in
the female chick. In the second stage, which begins about the time
of hatching, there is an increase in the size of the units of the ovary,
accompanied by yolk formation. At this time each ovum is in its
own follicle (Fig. 81), and is surrounded by a layer of cuboidal
cells and a theca. The theca is formed from the adjacent fibrous

fe a

Fic. 81.—Section of ovuminahen. 1. Nucleolus. 2. Nucleus. 3. Liquor
folliculi. 4. Stratum granulosum. 5. Follicular cells. 6. Theca folliculi.

7. Peripheral stroma.

stroma. The third stage, that of maturation, commences during the
development of the yolk and is complete after it has escaped to the
oviduct. Maturation consists of each cell’s dividing into two un-
equal parts. In each division the cell is split into a small cell known
as the polar body, which is cast off and disappears, and a larger cell,
which is the ovum proper. In this process half of the original
chromosomes are cast off.

Fertilization.—The sperm travels rapidly; experiments have shown
eggs to be fertile laid twenty-four hours after service by a male.

320 ANATOMY OF THE DOMESTIC FOWL

When the ovum is discharged into the ovarian eee it is surrounded
by spermatozoa.

After the male pronucleus has united with ite female pronucleus
in the single-celled ovum, there is a cleavage of the cell in the
long axis of the egg, making two cells; and then a cleavage at right
angles, which progressively continues, makes the mulberry-like
mass. The remaining content of the egg consists of food for the
development of the embryo. From this mass of cells before the egg
is laid the blastoderm is formed. The cells of the blastoderm are
differentiated into two layers. The superficial layer is the ectoderm
and the lower layer is the entoderm. In the newly laid egg the blasto-
derm may be observed. It is about 4 millimeters in diameter.
It has a transparent central area, the zona pellucida, which is located
over the subgerminal region. There is a peripheral, less transparent
area called the zona opaca.

In the fertile egg, as soon as it is subjected to the proper tempera-
ture, cell multiplication in the blastoderm begins. The first signs
of such change are noted in the pellucid area of the blastoderm
where embryonal traces appear in the form of the parallel lines
called the plice primitive, which diverge to form the cephalic
dilatation. At about this time takes place the formation of the
myelencephalous columns, in which the blood lakes expand in the
surrounding halones and in the tracts along which pass colorless
blood particles. These tracts extend from below the cephalic
expansion to the peripheral sinuses, as the proto-veriebre, which
begin to appear at the sides of the myelon. The red color is ac-
quired by the blood, and the heart by its movements, is made more
manifest as the punctum saliens. A distinct membrane, the serous
layer, is formed upon the germ and the blastoderm. The cephalic
end of the embryo rises from the surface of the blastoderm, and then,
curving down, sinks into it, forming for itself a kind of hood of the
serous layer. This hood gradually extends from the margin of the
fossa over the body, and, meeting a similar fold formed by the
projecting and incurved tail, closes over the germ on the upper side,
making a circumscribed cavity, which is the amnion. The progress
of differentiation of layers of the blastoderm has meantime, gone on
beneath. The serous layer is in part reflected from the vascular
and from the mucous layer. The mucous layer is concerned in the
formation of the intestinal canal; and beyond this part, which is at
first an open groove, the mucous layer expands over the yolk,

EMBRYOLOGY, OF THE CHICK 321

which it ultimately incloses, the margins of the vifellicle so formed
contracting and uniting at the side opposite the embryo at a sort of
cicatrix, to which the last part of the abdominal yolk adheres. The
vitellicle is richly vascular, and the surface next to the yolk is aug-
mented by ruge.

The fowl’s egg, at about the fortieth hour, shows the buds from
which the limbs are developed. A vesicle is seen to protrude near
the anal end of the intestine, which, rapidly expanding, spreads over
the embryo, acquiring a close adhesion to the amnion, but remaining
distinct from the vitellicle, over which it spreads. It finally en-
closes the albumen and interposes itself between the latter and the
lining membrane of the shell. Umbilical vessels are associated with
this membrane. Hunter called this membrane the allantois from
its containing urine, and Owen states that the sac which surrounds
the albumen acts as the chorion or placenta; for it is most probable
that from this surface the albumen is absorbed and the chick sup-
ported on its developmental food. The external part of the sac
apparently acts as lungs as it comes into contact with the shell of
the egg through pores of which there is an exchange of air. Oxygen
is consumed and carbon dioxide is given off. The blood in the
vessels of this membrane is in color more like arterial blood and that
in the interior more like venous blood.

The embryonic mass of the incubating egg always floats to the top
side. As the embryo grows it turns upon its left side, exhibiting a
profile view; it then indents the yolk, and finally almost divides it
into two parts.

The peripheral layers of cells rise from the margin of the germ
mass, and extend and contract toward the opposite pole. This
tract of germ substance is the primitive streak. Along the median
line it next forms a furrow, which stops short of the ends of the streak.
This streak terminates opposite the point from which the germ
begins, and swells into the head. The median furrow expands upon
it. The cephalic borders are next united by a thin layer of epithelial
cells above the furrow, converting it into a cavity, or ventricle. The
myelonal furrow is similarly convered by a layer, uniting the lateral
columns. The embryonal trace becomes longer, narrower, and
bends round the vitellus. A layer of epithelial cells forms a net-
work over the whole dorsal surface of the embryo. Oblique strize
appear in the broadening germ mass radiating from the primitive

streak. These indicate divisional segments. These beginnings
21

322 ANATOMY OF THE DOMESTIC FOWL

of aponeurotic septa probably accompany and support nervous
productions from the myelon columns.

Two transverse constrictions begin to divide the cephalic en-
largements into three lobes, the second and the third of which ex-
pand into vesicles. An accumulation of cells at the side of the
middle expansion appears to add greatly to its breadth. This
forms the basis of the eyes.

The differentiation and the confluence of the cell constituents
of the primitive streak have led to the formation of a pair of albu-
minous cords along the sides of the median furrow, forming the
myelon proper. The cells exterior to and above them are converted
into muscle and fibrous septa; and beneath the column is a jelly-
filled cylinder, with a transversely striated sheath, pointed at both
ends, forming the xotocord. Its anterior point passes a little in
advance of the acoustic vesicle. Beneath the notocord and sur-
rounding the blastema is stretched the vegetative, or mucous, layer
of cells, in contact with the yolk. ‘Both the head and the tail
of the now cylindrical embryo are liberated from the surface of the

- yolk. A fold of the blastema, reflected from the under part of the

head, sinks like a pouch into the yolk, and soon includes the rudi-
ment of the heart, like a bent cord, which begins to oscillate about
the seventh day. From the midline of the inferior surface of the
embryo, or its mucous layer, two longitudinal plates descend, diverg- .
ing into the yolk-substance, and form the primitive intestinal groove.

The ophthalmic vesicle elongates and curves outward until the
two ends almost come into contact. Between these two ends and
beneath the delicate tegumentary layer connecting them the crystal-
line lens is formed. About the same time, the otoliths appear in
the acoustic vesicles,which have now acquired a cartilaginous case.
The cerebral lobes begin to be formed by a small fold, rising laterally
and overlapping the forepart of the second enlargement, which
has expanded to greater breadth. The olfactory cavities appear as
small cutaneous follicles.

The two myelonal columns, expanding between the ear sacs and
receding so as to show the notocord beneath, bend upward and
inward, and unite, to be continued into the posterior of the optic
lobes, thus commencing the cerebellar bridge across the epencephalic
ventricle. The encephalic vacuities have begun to be filled by the
granular basis of the cerebellar substance.

The iniestinal groove begins to be converted into a canal at its

EMBRYOLOGY OF THE CHICK 323

two ends. Beneath the anterior end, and behind the heart, there
gradually accumulates the cellular basis of the liver.

_ The commencement of the development of the organ of hearing
is by a superficial depression of the cephalic blastema to meet the
_ process from the encephalon, which forms the acoustic nerve.
The lining of the depression becomes, on closure of the slit, the
proper tunic of the labyrinth.

The vesicle of the labyrinth swells into four dilatations, of which
three are ampullar and the fourth cochlear. The ampullar dilata-
tions extend into very slender canals, at first almost in the same
plane, by which they are. brought into mutual communication.
As the canals expand and elongate, they assume their characteristic
relative positions as external, superior, and posterior, the posterior
end of the external canal being extended beneath the posterior
canal. The cochlear dilatation curves as it elongates. An inner
layer becomes distinct from the common membrane and forms the
acoustic.lamina.

As in the development of the ear, so in the development of the
eye, the production of the nerve process from the cerebral center
is the first step; the infolding of the superficial blastema to meet
the nerve is the next. The so-called cutaneous follicle becomes a
circumscribed sac or vesicle, in which the changes and the develop-
ment next proceed, converting the vesicle into an acoustic labyrinth
or into an eyeball. In each case neural elements of two vertebra
become modified to lodge and to protect the sense organs, forming
respectively the recess called ofocrane and that called the ‘orbit.
The one is located between the occipital and the parietal vertebra,
and the other between the frontal and the nasal vertebra. The
part of the outer blastemal layer of the head which sinks to meet
the process from the mesencephalic dilatation, rapidly changes its
follicular into a vesicular state. The vesicle thus formed elongates,
bending around the cell mass in which the crystalline lens is formed,
and the meeting of the two ends results in forming the choroid
fissure at the lower part of the eyeball.

The mesencephalic process, or optic nerve, expands at the posterior
of the circular sac, and, in the course of mutation into eyeball,
lines its posterior part with a layer which becomes the retina. The
transparent layer covering the forepart of that sac and the inclosed
lens is formed into the cornea. Other layers of the sac are formed
into the choroid, the ciliary processes, the iris, and the pecten.

324 ANATOMY OF THE DOMESTIC FOWL

Of the appendages of the eye the membrana nictitans is the first
to develop. Then develop the lower lid and, last, the upper lid.

After the development of the essential organs of sense, the skin
is developed. Modifications of the skin form the outer ear and the
eyelids. Then are formed the maxillary arch, the hyoidean
arch, and the scapular arch.

The vessels which return the blood from the vitellicle are the
transverse and the longitudinal véfelline veins. The first are so
called because these trunks pass to the embryo at right angles to its
axis. They are the largest returning canals. The longitudinal veins
extend parallel with the axis of the embryo; they are of smaller size.
The right anterior Jongitudinal vein becomes the right precaval and
receives the remairis of the right transverse vitelline vein, as the
right vena azygos. The left anterior longitudinal vitelline vein is
also persistent as the left precaval, and enters in the mature bird,
as in the embryo, at the posterior or the lower part of the auricle.
The left transverse vitelline vein is also subsequently reduced, by
receiving only the vertebral veins of that side, to the condition of a
so-called azygos vein. The main trunk of the post-cava] is the result
of the returning vessels from the abdominal] viscera and the posterior
limbs at a later stage of development. There is but one principal
posterior longitudinal vitelline vein, and this anastomoses with the
left transverse vein as it eaters the embryo.

The auricle, which, by its dilatation of the left side, appears to be
double, receives the venous blood at its right division. The left
one, subsequently receives the veins from the lungs, is ultimately
separated from the left precava] and the.right auricle to which that
vein is conducted and restricted.

The ventricular part of the heart, at the second day of incubation,
is in the form of a bent tube, curving from behind downward, for-
ward, to the right and upward, continuing insensibly into the part
representing the aortic bulb, in which the septum first appears,-and
ultimately dividing the ventricle into two.

At this stage the piers of the maxillary arch appear as buds
from beneath the eyeballs. The naso-premaxillary process is above
their interspace. The piers of -the mandibular arch and those of
the hyoidean arch follow in close succession. The blastemal base
of the scapular arch projects slightly at the sides of the fovea
cardiaca; the piers, now separate, ultimately meet in front of the
heart, and accompany it in its retrograde course. The mesen-

EMBRYOLOGY OF THE CHICK 425

cephalon is the largest of the segments of the brain which are con-
nected with the eyeballs.

When the heart has assumed its form as such, distinct from the
great trunks rising from it, the two arteries from the base of the
ventricles appear. The artery to the right bifurcates, one division
supplying the head and the wings, the other. winding over the right
bronchus. That to the left also bifurcates. Its left division arching
over the left bronchus and anastomosing with the right arch a little
below and behind the apex of the heart. Its right division arches
over the back of the heart, bending to the right and anastomosing
with the right aortic arch just above the outer ductus arteriosus.
Each of these divisions of the left primary arterial trunks sends off
a branch to its corresponding lung. As the lung expands, and
especially at the beginning of the act of expansion toward theclose
of the period of incubation, the blood is diverted into thepulmonary
vessels, and the channels below them shrink and disappear. The
left primary artery is retained as the trunk of the pulmonaries, and,
through the changes in the interior of the ventricle, this artery comes
to discharge exclusively the ventricle corresponding to the right in
mammals. The retained aorta rises from the left ventricle.

The air-sacs begin at the lower point of the lung, appearing like
small hydatids, and extend further and further into the abdomen,
in front of the kidneys. They are at first full of fluid. Soon after
the development of the abdominal air-sacs others are developed.

The Jungs are at first free, but afterward begin to be attached to
the ribs and to the spine.

In the female embryo we first observe two oviducts, one on each
side of the basis, or stroma of the ovarium, which appears in a
relation to the primordial kidneys similar to that of the testes in the
male. At the period when the permanent kidneys have sent their
ureters to the cloaca, the oviducts have been developed as prolonga-
tions from that part, and, up to a certain point of development, they
are of equal size and Jength. Subsequently the left oviduct alone
continues to grow; the right remaining stationary or shrivels;
occasionally it may be discerned as a rudimentary in the mature
bird, but usually al] trace of it has disappeared before hatching.
The left oviduct expands above or at its free end into the infundibular
orifice, where its parietes are very thin. As it descends, these in-
crease in thickness, and the efferent tube gradually acquires the

326 ANATOMY OF THE DOMESTIC FOWL

Fic. 82.—Embryological studies.

A. 1, The chorion and allantois. 2, The allantoic cavity. 3, The amnion.
4, The yolk sac. 5, A small quantity of remaining albumin.

B. Brain tube of a chick 2514 hours old showing partly closed brain tube with
eleven folds of neuromeres.

C. The development of the alimentary tract. 1, Trachea. 2, Lung. 3,
Esophagus. 4,Stomach. 5, Pancreas. 6, Bileduct. 7, V-shaped loop of mid-
gut. 8, Cloaca. 9, Vitello-intestinal duct.

D. 1 to 6 inclusive, same as C. 7, Ceca. 8, Cloaca.

E. Kidneys, Wolffian bodies, and testes of an embryo chick. 1, The adrenals.
2, The genital. 3, Primitive oviduct. 4, Permanent kidney. 5, Ureters. 6,
Duct of primitive kidney which conducts the excretion into the cloaca.

F. A transverse section of a chicks’ head 48 hours of incubation. 1, Fore-
brain. 2, Pigmented layer of retina. 3, Ectoderm. 4, Nervous part of retina.
5, Optic stalk. 6, Invagination of ectoderm to form the lens rudiment.

EMBRYOLOGY OF THE CHICK 327

texture and form of an intestine. It is attached and supported by a
duplicature of the peritoneum.

At first, the right and the left ovaria are similar in size, but the
symmetry is soon disturbed by concentration of development in the
left ovary. The right ovary remains stationary and ultimately,
in most birds, completely disappears by the time the chick is ready
to emerge from the shell.

Three fetal membranes are developed, the chorion, the amnion,
and the allantois. There is also developed the yolk sac (Figs. 82 and .
83). The amnion is connected to the body wall at the umbilicus.
The amniotic fluid is found in this sac. The chorion is at first
surrounded by the albumen, but as the albumen is absorbed the
chorion comes in contact with the inner shell membrane. It is
probable that the chorion consists of ectoderm on the outside and of
mesoblast on the inside. The amnion, on the other hand, is formed
of mesoblast on the outside and ectoderm on the inner, or embryonal,
side. The allantois springs from the embryo soon after the fourth
day, and develops from the ventral wall of the primitive gut. By
some embryologists, the yoJk sac is included in the embryonic mem-
branes. It commences as the splanchno-pleure surrounding the
mass of yolk. It becomes smaller as the yolk is absorbed. At first

. its outline is round but later its walls become folded in. The yolk is
dissolved and absorbed by the entodermic lining of the sac, and is
carried to the embryo by veins called the vitelline veins (Fig. 83, No.
B, 4), which ramify on the walls of the sac.

Some time after the fourteenth day, the chick assumes a position
lengthwise within the egg shell so that the head is near the broad
end of the egg. The head is bent upon the chest and the beak is
usually tucked under the wing. Later the head assumes a position,
by a double curve of the neck, so that the beak is in contact with the
air cel]. About the fifteenth day, the coils of intestine, which
heretofore have been outside the abdominal cavity, are withdrawn
into the abdominal cavity, as is also the abdominal yolk sac. As the
chick pips out of the shell, the umbilicus becomes occluded.

The outer upper part of the tip of the beak is provided with a
short, stout, spike-like arrangement, called the egg tooth. On the
twentieth day this part of the beak is forced against the wall of the

. egg and gradually breaks through the egg shell. The breathing by

the lungs commences some time before hatching; this is evidenced by
the chick within the shell giving chirping sounds.

328 ANATOMY OF THE DOMESTIC FOWL

Fic. 83.

A. Longitudinal section of chick, 4 days incubation. 1, Cephalic fold. 2,
Caudal fold. 3, True amniotic cavity. 4, Epiblast. 5, Somatic mesoblast. 6,
Visceral mesoblast. 7, Hypoblast. 8, Future anua still closed. 9, The allan-
toic vessicle. 10, The mesentery. 11, Intestine. 12 and 13, Yolk sac. 14,
Cavity of true amnion. 15, The mouth. 16, Pleuro-peritoneal cavity. 17,
Fore gut.

B. Membranes of the chick at the third day of incubation. 1, Membrane
surrounding albumin. 2, Amnion. 3, Allantois. 4, Vitellicle.

C. The fore part of an embryo chick at the second day. 1, Mesencephalon.
2, The eye. 3, Olfactory organ. 4, Mandibular arch. 5, Maxillary arch.
6, Maxillary arch. 7, Hyoidean arch. 8, Scapular arch. 9, Depression organ
of hearing. 11, Process from encephalon for union with nerve of hearing.

D. Primitive .blood-vessels at second day of incubation (Owen). 1, Meso-
cephalon. 2, The right anterior longitudinal vein. 3, The eye. 4, The man-

EMBRYOLOGY OF THE CHICK 329

The circulation of the blood is somewhat like the circulation in the
fetus of quadrupeds. The primitive tubular heart (Fig. 83, No. D,
8) is bent in S-shape; the two ends are connected with blood-vessels;
and later, by the development of the septa, the cavities of the adult
heart are defined. The foramen ovale is found in the median
septum. This opening brings the right and the left side into commu-
nication. The septa between the cavities of the heart are completed
by the end of the sixth day. The two vitelline, or omphalo-mesen-
teric, veins carry the blood containing the nutrients from the yolk
sac to the liver, where it is mixed with the blood drained from the
intestines by the portal vein, and this blood is finally carried by
the posterior vena cava into the right auricle of the heart. From
here it passes through the foramen ovale to the left auricle; from the
left auricle it enters the left ventricle, from which it is forced into
the aorta, and then out into the systemic circulation. Practically
all, if not all, of the blood of the pulmonary artery is sent into
the aorta through a connection with this vessel called the ductus
arteriosus.

Down appears about the thirteenth day of incubation. There are
two kinds of down on the chick, one Jong, which comes first, about
two or three days before hatching; a second, or fine, down forms at
the roots of the other. As the embryo develops the air cell, at the
large end of the egg which is developed between the two shell
membranes, or membrane putamine, gradually enlarges.

dibular arch. 5, The hyoideanarch. 6,Scapular arch. 7, The same. 8, The
ventricular portion of the heart. 9, The right transverse vitelline vein. 10,
Posterior longitudinal vitelline vein. 11, Vertebral vein. 12, Tributaries of
same. 14, Theauricle. 16, Aortic bulb.

E, A transverse section of chick embryo, 29 hours incubation. 1, Neural
canal. 2, Neural crest. 3, Somatopleure. 4, Splanchnopleure. 5, Omphalo-
mesenteric vein. 6, Aorta. 7, Notocord. 8, Pleuroperitoneal cavity.

F. Chick embryo at the ninth day of incubation. 1, Allantois. 2, Amnion.
3, Air cell-at large end of the egg. 4, Egg shell. 5, Outer shell membrane. 6,
Inner shell membrane. 7, Yolk sac. 8, Albumin (Bradley).

OUTLINE FOR LABORATORY STUDY OF THE CHICK

The objects of laboratory study of the embryos are as follows:
1. To study the living embryo.
2. To study the entire embryo:
With the dissecting microscope, as an opaque object.
With the compound microscope after killing, hardening, clarifying,
and mounting.
3. To study embryos by dissection, in later stages.
4. To study the serial sections with the compound microscope.

THE LIVING EMBRYO

The egg is opened under warm physiological salt solution: 0.8
per cent. sodium chlorid in distilled water heated to a temperature
of 38°C.

Gradually pick away the shell at the large end. Note that there
are two membranes and an air cell. Strip of the membranes.
When sufficient shell and membranes have been removed from the
large end, invert the open end of the egg in the salt solution and
allow the contents to flow out. Care must be taken not to break the
yolk. The embryo, or blastoderm, lies upon the surface of the
yolk, which is usually turned with this body uppermost. Separate
the blastoderm by cutting around the outside of the area vasculosa.
In doing this a small pair of slightly curved scissors isneeded. After
the embryo, or blastoderm, has been separated, gently float it into
a watch crystal with the flat bottom submerged in the salt solution.
The watch crystal with its contents may now be gently lifted out.
Next remove the vitelline membrane. The vitelline membrane is
the delicate transparent membrane covering the blastoderm. The
embryo is now ready for study.

THE PREPARATION FOR STUDY OF ENTIRE EMBRYOS AND SECTIONS

The following processes may be used in killing embryos up to
four days, or ninety-six hours, of age. After removing the embryo
as described above, spread the blastoderm out in the watch crystal
and pipette off the salt solution. Allow it to stand till the edge of

330

OUTLINE FOR LABORATORY STUDY OF THE CHICK 331

the tissue begin slightly to adhere. Then slowly add the killing
fluid by aid of a pipette, dropping it on the center of the embryo.
The pipette must be held low or the mechanical interference will
dislocate the parts.

Older embryos are submerged with their membranes intact into
the killing fluid. The quantity of fluid should be several times the
bulk of the specimen. Kleinenberg’s picrosulphuric. acid may be
used as a killing fluid. This fluid is a saturated solution of picric
acid plus 2 per cent. sulphuric acid, to which is added twice its
volume of water.

Chick embryos from one to two days old should be left in this
fluid from one and one-half to six hours. Embryos.from two to
four days old two and one-half to six.hours. Remove the specimen
from the killing fluid, and place it in 70 per cent. alcohol. Change
the alcohol every twenty-four hours until the color ceases to come
out of the embryo. Preserve in 80 per cent. alcohol.

If the specimen is to be mounted whole, transfer it from 80 per
cent., then to 50 per cent., then to 35 per cent., and, finally to
water. Small embryos should remain in each fluid thirty minutes
and large ones sixty minutes.

The following method may be used for staining embryos: Dilute
Delafield’s hematoxylin with four times its volume of water. To
every 6 cubic centimeters of this diluted hematoxylin, add one drop
of Kleinenberg’s undiluted picrosulphuric acid, and Jeave specimen in
the fluid thus prepared until it is stained through. This will require
from one to three hours. Now pass up through the series of alcohols
to 7o per cent. Next extract the excessive stain with 1 per cent.
hydrochloric acid in 70 per cent. alcohol. Wash repeatedly with
70 per cent. alcoho] to free from the acid; then transfer the specimen
to 80 per cent. alcohol and leave in this for several hours for com-
plete removal of the acid; then transfer to 95 per cent, alcohol for
thirty minutes. Allow the specimen to remain in absolute alcohol
for one hour. Introduce a layer of oil of cloves or xyJol beneath the
alcohol. This may be done by gradually allowing the fluid to run
down the side of the bottle. After the embryos have sunk into the
oil and begun to appear transparent, remove the fluid and add fresh
oil. After the specimen is sufficiently transparent, mount in
balsam, supporting the cover slip so that it will not rest on the
embryo.

- In staining for section, place the embryo in borax carmine from

332 ANATOMY OF THE DOMESTIC FOWL

the 50 per cent. alcohol and leave twelve hours. Then wash in 50
per cent. alcohol; after which transfer to 70 per cent. alcohol for six
hours. Clarify in oil of cedar or oil of cloves, and place in melted
paraffin for two hours. Imbed in paraffin, and section.

Embryos may be hardened, imbedded, and sectioned after the
usual methods, using either paraffin or celloidin, and the sections
stained with hematoxylin and eosin after sectioning.

POINTS TO BE OBSERVED IN THE STUDY

i. THE EMBRYO TWENTY-NINE TO THIRTY-FOUR HOURS OLD WITH
FROM TEN TO FOURTEEN SOMITES.

A study of the egg.

In opening the egg, observe that the shell membranes are double.

Observe that the shell is porous. :

Note the air cell at the large end of the egg and note that the space
or cell lies between the outer and the inner shell membrane.

After the egg contents have dropped into the salt solution, note
extending from the ends of the yolk the twisted denser cords of
albumen. These are the chalazz, which act as stays to the yolk.
Note that the yolk is surrounded by a delicate membrane. This
is the vitelline membrane. The yolk is the true ovum and serves
as food for the developing embryo.

A study of the living embryo.

Note the amount of yolk that is covered by the blastoderm.
Note the slipper-shaped, transparent center of the blastoderm.
This is the area pellucida. In the center of this there is a narrow
white streak. The area.opaca is the area lying external to the area
pellucida. In this there is the area vasculosa.

A study of the embryo entire, including the vascular area.

The blood islands show as irregular deeply stained masses in the
vascular area. At this stage they are inclosed in wide anastomosing
tubes, the extra-embryonic blood-vessels, which open peripherally
into the bounding sinus terminalis.

The following structures may be identified:

The neural tube forming the axis of the embryo. In the anterior
region may be noted the forebrain, the optic vesicles, the midbrain.
The hindbrain is subdivided into the neuromeres. The cord, or
myelon, of the neural tube back of the hindbrain is closed in front
but is open behind.

OUTLINE FOR LABORATORY STUDY OF THE CHICK 333

The head projects above the blastoderm. ‘The fold which unites
the ventral surface of the head with the blastoderm is called the
head fold.

The diverging folds of the myelon encloses the primitive streak.

On each side of the neural tube are the mesoblastic somites. The
series is continued behind by the undivided segmental plate.

The heart is beneath the hindbrain. The portion of the body
cavity in which it lies, is bounded in front by the head fold and behind
by the diverging limbs of the splanchno-pleure. Its posterior or
venous end receives the vitelline veins from the vascular area. The
anterior or arterial end is prolonged into the ventral aorta.

Note that the axis is somewhat bent.

The head fold of the amnion is noted to extend over the anterior
end of the head.

A study of the transverse sections.

The sections about 20 micro-millimeters thick should be cut serially,
and so mounted. Knowing how many micro-millimeters the
embryo is in length will enable one to make a diagram of the fetal
structure in the study of the series of transverse sections. The
sections should be drawn in the order studied so as to obtain relative
structural ideas.

With the microscope study the following regions:

. Optic vesicle.

. Midbrain.

. Posterior half of the heart.

. Myelon in the closed region.

. Myelon in the open region.

. Through the primitive streak.

. THE EMBRYO TWENTY TO TWENTY-FOUR HOURS OLD WITH FROM
TWO TO SIX SOMITES.

Compare the parts in this embryo with those of the embryos from
twenty-nine to thirty-four hours old. Note and describe the rela-
tions of the embryo, the area pellucida, and the area opaca. Note
how much of the yolk the blastoderm covers.

In studying the entire embryos, note the condition of the medul-
lary plate. Observe if the tube is formed in any part; how far back
the head plate extends, if the heart can be seen; and if the primitive
streak is longer or shorter than in 1.

Study relations of structures and make drawings through the point

Han PWD

334 ANATOMY OF THE DOMESTIC FOWL

of divergence of the walls of the fore gut; also through the somatic
region, and through the primitive streak.

Study all parts, as the head fold, the heart, and the fore gut.

3. THE EMBRYO FORTY-FOUR TO FORTY-EIGHT HOURS OLD WITH
TWENTY-FOUR TO TWENTY-NINE SOMITES.

Remove the embryo with the entire area, and preserve it.

Note and carefully describe the changes visible to the naked eye
since the thirty-fourth hour.

In making a study of the entire embryo we note there has been a
rapid growth of the dorsal surface of the head, which has become
more bent. This bend, in the region of the midbrain is called the
cephalic flexure. The forebrain and part of the midbrain form
almost a right angle with thc rest of the head. The head is com-
pressed laterally and free from the blastoderm. The dorsal side
of the trunk is turned up, and there is a twisting of the axis of the
embryo just back of the heart. The tail fold begins at about this
time and may or may not be visible. The optic vesicles are rela-
tively smaller in relation to the brain than in 1. Note the part
of the forebrain to which they are attached. Observe the.inner and
outer layers of the retina, the lens, the choroid fissure, and the
cavity of the vitreous humor.

Note the auditory vesicles and whether or not they are closed sacs.

Note that the heart has grown in length and has become doubled
on itself. The two ends are fixed. Note the relation of the heart
to the afferent and efferent blood-vessels. Note that two, and
possibly three, visceral pounches are visible. Note whether or not
they are ventral to the midbrain. The first, the hyomandibular
pouch, is bounded in front by the first visceral, or mandibular, and
behind by the second visceral, arch. The second pouch is bound in
front by the hyoid, and behind by the third visceral arch. The.
third pouch is bounded in front by the third visceral arch, and
behind by the fourth. Note the number of mesoblastic somites and
the condition of the mesoblastic segmental plates.

Note how far back the foregut is closed. Locate the head fold of
the amnion, and note how far back it is closed. Note changes that
have taken place in the vascular area. In studying the sections it
will be found that a section cut transversely to the trunk will pass
horizontally through the forebrain and through the midbrain.

Study a section through the trunk a short distance behind the
heart. Observe the elevation of the axis of the body. Note the

OUTLINE FOR LABORATORY STUDY OF THE CHICK 335

way in which the lateral folds, or the lateral] limiting sulci, in the
somatopleure, delimit the embryonic from the extra-embryonic area.

Note the appearance of the mesenchyme, the approximation of
the two dorsal aorte, the appearance of the amniotic folds. Ob-
serve in the mesoderm the posterior cardiac veins, and the myo-
tomes, or muscle plates. The sclerotome is made up of the mass of
mesenchyme between the myotome, on the one hand, and the
neural tube and the notochord, on the other. Note the folding
of the splanchno-pleure, and note if there is present the Wolffian
duct, or the nephrotome.

Study sections through the optic vesicles. Note if there is the
beginning of the lens. Do you note the diverticula of the pharynx?
Can you identify the closed amnion and the chorion?

Study sections through the auditory pit. Note fusion of the gill
pouches with the ectoderm. Note the blood-vessels. Study sec-
tions through the region of the heart, through the roots of the vitel-
line veins, and through the primitive streak, if it is still present.

For this study it will appear that the anterior end has developed
in advance of the posterior end. The tail fold has probably just
begun.

Write a description of the pharynx, and of the circulation at this
stage.

4. THE EMBRYO SIXTY-EIGHT TO SEVENTY-TWO HOURS OLD WITH
CERVICAL FLEXURES FORMED.

In a study of the living embryo note the changes visible to the
naked eye since forty-eight hours old. Note the difference in the
blood-vessels of the vascular area. Name the arteries and veins.
Note the beating of the heart.

In a study of the entire mount note that a second, the cervical
flexure, has appeared in the head. Note that the tail fold is well
formed. Note the position of the embryo on the blastoderm. De-
termine if the amnion is completely closed. Note the olfactory
pits on the ventral surface of the head, a short distance in front of the
optic stalks. Note the telencephalon, a rudiment of the cerebral
hemispheres and an extension of the primary forebrain. It is
bilobed anteriorly. The optic stalks are attached to the floor near
the anterior end of the thalamencephalon. Note the infundibular
region, which is the depressed region behind the optic stalks. In
the roof of the thalamencephalon there is a short diverticulum, the
epiphysis. The mesencephalon, or midbrain, forms the apex of

336 ANATOMY OF THE DOMESTIC FOWL

the cranial flexure, and is united- to the hindbrain by a narrow
isthmus. The metencephalon, or rudimentary cerebellum, appears
as a thick portion on the most anterior division of the hindbrain.
The rest of the hindbrain is provided with a transparent roof and
constitutes the myelencephalon, or the rudimentary medulla ob-
longata. Observe the inner and the outer wall of the optic cup, the
lens, the choroid fissure, and the posterior, or vitreous, chamber.

Note the form of the otocyst, or auditory sac. Note above which
visceral arch it lies. Note the number of visceral clefts. The
visceral arches are formed by the thickening of the walls of the
bounding clefts. The visceral arches are as follows: the first is
the mandibular, or hyomandibular, arch, which is in front of the
first cleft. From this there is developed the lower jaw. Note if
there is a maxillary process arising from the dorsal angle of the
arch. The second arch is the hyoid arch, which is located behind
the first cleft. Then follow in order the third, the fourth, and the
fifth visceral arches. Note above the mandibular arch the rudi-
mentary trigeminal ganglion, and above the hyoid arch the rudi-
mentary acoustico-facialis. The latter is in contact with the anterior
walls of the auditory sac. The rudimentary glossopharyngeal
ganglion is noted above the third visceral arch. The vagus, or
pneumogastric, ganglion is located above the fourth and the fifth.
Note the form and the postion of the heart. Note the anterior and
the posterior limb rudiment in the trunk.

In a study of the sections it is found that cuts transverse to the
trunk pass about horizontally through the forebrain. At this age
the following sections of the embryo should be studied:

First, through the hindbrain, at which level will be noted the
auditory sacs, the neuromeres, the trigeminal, the acoustico-facialis,
and the glossopharyngeal] and the vagus ganglion.

Second, through the upper part of the pharynx, at which level
will be observed the midbrain, the hindbrain, the visceral pouches,
the nerves, and the blood-vessels.

Third, through the choroid fissure of the optic cups. Note the
parts of the eye, and, on the other side of the section, the heart.

Fourth, a study of a section through the olfactory pits.

Fifth, a study of a section through the pancreatic and the hepatic
dverticula.

Sixth, a study at the beginning of the allantois through the hind-
gut.

OUTLINE FOR LABORATORY STUDY OF THE CHICK 337

At this age it is of interest to study the systems of organs. Ob-
serve the manner in which the splanchno-pleure folds to form the
walls of the intestine. Note the commencement of the mesentery.
Note that the foremost part of the alimentary tract is formed from the
stomodeal invagination of the ectoderm. The hypophysis is formed
from a dorsal outgrowth of this. Note its relation to the brain.

The following structures are formed from outgrowths of the
ectoderm at this stage:

First, the visceral pouches.

Second, the median rudiment of the thyroid. This is an out-
growth from the pharynx between the two hyoid arches.

Third, the rudimentary lungs, which develop in a pair from a
median ventral diverticulum of the alimentary tract, just behind the
last visceral pouch. The esophagus is just posterior to this. The
esophagus, very short at this stage, is continuous with a slightly
wider part that develops into the stomach.

Fourth, the first liver diverticulum, and, at a short distance
posterior to this, the second liver diverticulum.

Fifth, the pancreas is at a point where the intestine opens ven-
trally. It first appears as a slight thickening of the dorsal angle of
the intestine.

Sixth, the ventral wall of the hind-gut forms a wide evagination.

Seventh, the beginning of the allantois.

After the whole series of transverse sections have been studied and
drawn, construct a longitudinal section of the fetus, including a
reconstruction of the alimentary tract.

At this stage the heart is a simple tube. The following divisions
are distinctly visible: the auricular portion, the ventricular portion,
the sinus venosus, and the bulbus arteriosus. The union of the two
ductus Cuvieri and the ductus venosus form the sinus venosus. The
two.ductus Cuvieri are formed by the union of the anterior and the
posterior cardina] veins. The ductus venosus is formed by the
union of the small right and the large left vitelline vein. These
latter veins return the blood from the yolk sac. The sinus venosus
empties into the single auricle above which it is located. The
single auricle is later divided into two chambers, the right and the
left auricle. At this stage it is widest in the Jateral direction.
The auricle empties directly into the ventricle. The ventricle lies
ventrally and behind the auricle. This location is due to the bend-

ing of the heart at this stage of development. Its hindmost portion
22

338 ANATOMY OF THE DOMESTIC FOWL

forms the future apex of the heart. If the series -of sections be
studied from the posterior forward, the ventricle will be first to
appear in the sections. Just beneath the auricular portion of the
heart there is the bulbus arteriosus. The bulbus arteriosus soon
divides into a number of aortic arches. There is an ascending pair in
each of the visceral arches. The dorsal aorta is formed by the union
of the aortic arches above the visceral arches. The aortic arches are
first continued a short distance forward as the carotid arteries. The
dorsal, or posterior, aorta passes backward under the notochord.
The dorsal aorta divides into two parallel aortz which give off on
each side the vitelline arteries. Note other branches of this aorta.

The veins at this stage consist of the anterior and posterior cardi-
nal, the ductus venosus, the ductus Cuvieri, and the vitelline veins.

Make drawing of the circulatory system after a completion of the
study of the series of sections.

Make a study of the nervous system according to hints already
given. '

The dorsal and the ventral roots of the spinal nerves are given off
separately, and secondarily unite. From the neuroblasts of the cord
there are at regular intervals outgrowths representing the ventral
roots. From the neural crest there develop segmental collections
of neuroblasts which form the spinal ganglia, from which the dorsal
spinal nerve roots develop. In fact this developmental stage can
be observed in embryos only forty-eight hours old, first appearing
as a line of cells springing on each side from the angle between
the neural canal tube and the external epiblast. In the section
from the embryo seventy-two hours old there are observed the
rudiments of the development of these spinal nerves. Four pri-
mary ganglia develop in the neural crest of the head. These
ganglia are as follows: the acoustico-facialis ganglia, which is located
over the hyoid arch; the ganglia of the trigeminus, which is located
over the mandibular arch; the ganglia of the glosso-pharyngeus,
which is located over the third visceral arch; and the ganglia of the
vagus, which is located over the third and the fourth visceral cleft.

In this stage of development the trigeminal and the acoustico-
facialis are clearly visible.

On each side and dorsal] to the aorta is noted the Wolffian body,
or mesonephros. The Wolffian body (Fig. 82 £) .consists of a
series of tubules imbedded in the mesenchyme. The openings into
the Wolffian duct lie just beneath the cardinal vein.

OUTLINE FOR LABORATORY STUDY OF THE CHICK 339

In a study of the Wolffian duct determine just how far anteriorly
and how far posteriorly it extends. Note whether it empties into
the cloaca.

Each tube beginning in a blind extremity is later dilated. It has
a thin wall, and is situated near the median portion of the Wolffian
body. The tubule proper passing transversely, opens into the duct.
The upper wal] of the thin-walled part is invaginated by a mass of
mesenchyme that receives a small vessel from the dorsal aorta. The
Malpighian corpuscle; consisting of a glomerule and Bowman’s cap-
sule, is thus established. In the study of the four days old chick
note the further development of these parts.

In a study of a chick four days, or ninety-six hours old, note to
what extent the yolk is covered by the blastoderm. It will be noted
that the embryo lies in the extra-embryonic cavity. This cavity is
bounded above by the chorion and below by the splanchnopleure.
In removing the amnion from the embryo, note the relation to the
somatic umbilicus. Note the relation of the splanchnic umbilicus
to the splanchno-pleure. What relation has the allantois to the
above?

In examining the head, locate the cerebral hemispheres, and note
their development. Locate the pineal gland. Note changes in the
olfactory pit and the eye. Locate the lens and the choroid fissure.
Note that the maxillary process of the mandibular arch lies beneath
the eye and behind the olfactory pits. Note the otocyst and the
relations of the other arches to the above structures.

In a study of the trunk, note the tail, the allantois, Wolffian
ridges, the heart, and the condition and the position of the rudi-
mentary limbs.

Make drawing of embryo from the side view. Carefully cut off
the head immediately behind the last visceral arch, and study and
draw the structures observed on the ventral side. Note the maxil-
lary processes, the mandibular and the hyoid arch, the nasal pits,
and the fronto-nasal process, which is just beginning its development.

In a study of transverse sections observe from your drawing at
what level the section is made. Study and draw a section made
through the region of the anterior limbs. Note the spinal ganglion,
the muscle plate, or myotome, the condensation of mesenchyme
around ‘the notochord, the pancreas, the liver, and the intestine;
and note the distribution of the mesenchyme. Note the ventral
roots of the spinal nerves, and the neuroblasts in the spinal cord.

340 ANATOMY OF THE DOMESTIC FOWL

In sectioning the embryo from before backward, the first sections
will pass horizontally through the hindbrain and the midbrain
region. Note the parts, including the auditory vesicle. In the
first series of sections also, locate the ganglia of the pneumogastric,
or vagus, the acoustico-facialis, the trigeminus, and the glosso-
pharyngeal nerves. Note the notochord and the cardinal veins.
After the disappearance of the ear, we observe the midbrain, which,
is Jocated at one end of the section, and the cord at the other end.
The region between lies just above the pharynx. In the following
series study the visceral arches. Note the third pair of cranial, or
motor ocular, nerves. This latter nerve springs from the floor of
the midbrain. From the ventral prolongation of the floor of the
thalamencephalon there arises the infundibulum. The hypophysis
is located just beneath the infundibulum. At this stage the hypo-
physis appears as a tube to empty into the mouth. This is an in-
growth of the oral epithelium.

In a study of a section through the center of the eye we should
observe the lens and optic staJk. This is in the region of the optic
chiasm. Note the choroid fissure and the pineal gland, the latter
appearing just beyond the eyes. Just forward lies the telencephalon,
or rudiments of the cerebral hemispheres.

In a study of the alimentary tract we note that the mouth is
bounded by the mandibular arches. Note the maxillary processes,
and the ventral surface of the head. A finger-like diverticulum,
extending from the roof of the ruptured double membrane, formerly
separating the pharynx from the arches, forms the hypophysis.
The great development of the visceral pouches makes the pharynx
rather complex. In studying sections horizontally through the
pharyngeal region note the various visceral arches and pouches.
Note the arteries of the thyroid diverticulum.

In the series note the changed development of the lung rudiments,
the glottis, the esophagus, the trachea, and the bronchi. The bron-
chi appear in pairs. Note that the liver has assumed proportions,
and that it surrounds the common trunk of the vitelline veins,
which it divides into two parts. The sinus venosus lies close to the
heart. The ductus venosus is also surrounded by the liver. Above
the tip of the ventricle we note a dilatation which represents the
stomach. The hepatic, or bile duct is located immediately behind
the stomach. This duct is formed by the fusion of the right and the
left duct. Locate, draw, and describe the pancreas; trace the intes-

OUTLINE FOR LABORATORY STUDY OF THE CHICK 341

tine; locate the splanchnic umbilicus, or yolk stalk; locate the allan-
tois stalk, and trace its connection with the hind-gut.

In the series, locate and study the Wolffian ducts, the beginning
of the Miillerian duct, the embryonic kidney, or mesonephros, the
permanent kidney, or metanephros. The urino-genital ridge is
made up of all the above except the last named. The urino-genital
ridge forms a rounded projection on each side of the mesentery into
the dorsal angles of the body cavity: ee

The Wolffian ducts empty into the cloaca. There are two ducts
which may be traced far forward, and which are found to extend
backward along the lateral margin of the ridge to the cloaca. Along
the greater part of their length we note tubules emptying into them.

Beginning near the anterior end of the urinogenital ridge, we note
that the Miillerian ducts arise from a thickened line of epithelium.
The greater part of the ridge is formed by the mesonephros. This is
made up of a series of tubules in each of which we may distinguish
two parts as follows: a tuft of capillaries from the aorta forming the
glomerules, surrounded by a thin walled invaginated capsule, mak-
ing up the Malpighian corpuscle; and the tubules proper. The
tubules lead from the corpuscles, or glomerules, to the Wolffian duct.

The germinal epithelium constitutes the essential portions of the
gonad, or ovary, or testis. The germinal epithelium arises from a
thickening of the peritoneum of the median wall of the ridge. The
gonad is found near the anterior end of the ridge. At about this
age of the embryo there should appear the primitive ovary or testis.
Near the posterior termination of the Wolffian duct and from the
dorsal diverticulum there arises the ureter, or metanephros duct.

In these series there should be studied the heart and circulation,
which will be found similar to the sections from the embryo seventy-
two hours old.

Work out a summary of the relations of the allantois and the
yolk stalk to the intestines; the relations of the Wolffian ducts to the
intestines; the origin of the ureters from the Wolffian ducts; the
relations of the lungs, the liver, and the thyroid gland; the relations
of the blood-vessels; a study of the muscle plates; the relations of
epiphysis, hypophysis, infundibulum, mouth, and pharynx; the
relations of the vagus, or pneumogastric, trifacial, acoustico-facialis,
and glossopharyngeal nerves to the visceral arches.

In addition to the study of embryos at the end of each of the
first four days of incubation, a study should be made of preserved

342 ANATOMY OF THE DOMESTIC FOWL

museum specimens each of which represents the development of a
day up to and including the twenty-first day.

THE DERIVATIVES OF THE GERM-LAYERS

From the three primary germ-layers are developed the various
tissues and organs of the body by metamorphoses which may be
referred to the two fundamental processes of specialization, or the
adaptation of structure to function, and of unequal growth, which
latter results in the formation of folds, ridges, and constrictions.

From the ectoderm are produced:

The epidermis and its appendages, including the nails, the epi-
thelium in connection to the feathers and the feathers.

The infoldings of the epidermis, including the epithelium of the
mouth, epithelium of the salivary glands and the anterior lobe of the
pituitary body, or hypophysis. .

The epithelium of the nasal tract with its glands and communicat-
ing cavities.

The epithelium lining the external auditory canal, including the
outer stratum of the membrana tympani.

The lining of the anus.

The epithelium of the conjunctiva and of the anterior part of the
cornea, the crystalline lens.

The spinal cord, the brain with its outgrowths, including the
optic nerve, the retina, and the posterior lobe of the pituitary body.

The epithelium of the inner ear.

From the entoderm are produced:

The epithelium of the respiratory tract.

The epithelium of the digestive tract, from the back part of the
pharynx to the anus, including its associated glands, the liver, and
the pancreas.

The epithelial parts of the middle ear and of the eustachian tube.

The epithelium of the thymus and the thyroid bodies.

From the mesoderm are developed:

Connective tissue in all its modified forms, such as bone, cartilage,
lymph, blood, fibrous and areolar tissue.

' Muscle tissue.

All endothelial cells, as of joint-cavities, bursal sacs, lymph
sacs, blood-vessels, pericardium, and endocardium, pleura, and
peritoneum.

The spleen.

OUTLINE FOR LABORATORY STUDY OF THE CHICK 343

The kidneys and ureters.
The testicles and the system of excretory ducts.
The ovary and oviduct.

PREPARATION OF STRUCTURES FOR STUDY

It is hoped that the following suggestions will be helpful in the

laboratory work.
. Directions for Dissecting Muscles:—The muscles that are brought
into great play in movements of the bird’s limbs are dark carmine
in color, while those which are not brought greatly into use are pale
or white in color. :

The tendons are made up of white fibrous connective tissue, are
very dense, and pearly white in color.

In securing a bird for dissection of muscles it is best to select one
in rather poor flesh, as the fat is annoying. The bird may be
chloroformed or killed in a bell jar by aid of illuminating gas.
After the bird is dead pluck all the feathers and immerse it in a 10
per cent. solution of formaldehyde or of 80 per cent. alcohol. It is
best to puncture the abdominal wall so that the fluid may at once
fill the abdominal cavity and more readily gain access to the chest
cavity; and to puncture the skin at various points so that the liquid
may more quickly become disseminated among the muscular struc-
tures. Post-mortem changes quickly take place if these precautions
are not taken. The liquid surrounding the carcass should be at
least twice the quantity of the bulk of the carcass.

The first dissection should be to lay bare the dermal muscles.
The dermal muscles are of two kinds, true dermal and dermo-osse-
ous. The dermal muscles have their origin and insertion in the skin,
and control the movements of the different groups of feathers. The
dermo-osseous have their origin on some part of the skeleton, and
insert to the integuments.

The derma] muscles vary with the characteristics of the bird, we
do not find all the known dermal muscles in any one specimen. A
cock of the Cornish breed will show these muscles best developed.
Birds possess an enormous system of minute muscles divided up into
an infinite number of fasciculi, to act harmoniously upon the feather
quills and to agitate collectively the plumage. By the aid of a low-
power lens the action of the feather muscles in the large quill-butts
of the wing or the tail may be studied.

The muscles may be studied in groups as outlined in the text.

344 ANATOMY OF THE DOMESTIC FOWL

Make an incision through the skin down to the bone on the superior
part of the head, parallel and close to the base of the upper mandible,
and extending completely across. From the outer end of this make
an incision backward and down to the skull and posteriorly. The
muscles of the upper part of the neck will then be exposed. The
straight incision should extend to about a half inch on the inside of
the upper eyelid of the same side. Reflect the flap of skin from the
top of the skull, and carefully examine the under side of it in the
* median line, where it overlies the fronta) region. The dermo-fron-
talis will be observed if it be present. In many birds, especially in
females, it may not be discernible, and may be considered absent.
To expose the circumconcha make an incision completely around
the ear; then carefully dissect to the ear base. A dermal circular
muscle should be observed. To expose the dermo-temporalis
extend the longitudinal incision down the back of the neck to a
point between the clavicular heads, carrying it just through the
skin and about one-fourth of an inch to the side of the median line.
Remove the skin from the throat and the anterior portion of the
chest. Lay open the alar and parapatagial duplicatures of the skin.
This exposes a number of dermal muscles. The dermo-temporalis
is now observed to extend from a small depression just above and
anterior to the temporal fossa. It makes slight attachments to the
temporal muscle, which it covers, and extends backward as a thin
ribbon-shaped muscle, the fibers blending with those of the cleido-
trachealis, and becomes lost upon the skin in front and opposite the
shoulder-joint. At times its fibers blend with those of the dermo-
tensor patagii.

As the musculature of the fow] is loosly arranged, the rest of the
dissection is easily done if care be exercised.

The ligaments may be dissected after the completion of the study
of muscles, using the same subject or, a two pound broiler be pre-
pared by killing in the gas chamber, plucking the feathers and
parboiling just till the flesh becomes tender and is easily removed,
it will be observed that all structures can be removed from the
points exposing the ligaments distinctly. The ligaments appear
swollen and more easily observed for study.

Directions for the Study of the Viscera.—Carefully remove the
right and the Jeft abdominal and thoracic walls, allowing a strip
of tissue to remain in the median line to hold the organs in their
normal position. To open these cavities it is necessary to use the

OUTLINE FOR LABORATORY STUDY OF THE CHICK 345

bone saw and the scalpel. The organs may now be studied from
each side. To make a longitudinal section through the median line,
select a smal] bird, one weighing not more than 2 pounds, kill,
and preserve in a so per cent. solution of formaldehyde for three
days. Then with a sharp, thin, long-bladed knife make an incision
at one sweep through the median line of the body down to the back
bone, and with the bone saw section through the vertebrz. If it is
difficult to cut through the breast-bone, saw through before making
the incision. In small birds the entire cut may be made without
the aid of the saw. ,

Directions for the Study of Arteries.—Arteries should be injected.
Veins are usually more or less filled with blood so that the tracing of
these is not so difficult as the tracing of uninjected arteries. Nerves
are white and no difficulty is usually encountered in tracing them.

The courses of arteries, veins, and nerves are side by side, and
many of them, as in mammals, are arranged in the order of veins,
arteries, nerves, the veins being in front.

The injection apparatus consists of the following parts: air-com-
pression chamber, to which is attached a pressure pump. A mano-
meter made of glass tubing 6 millméters in diameter, inside measure-
ment. This tube is partly filled with mercury, and a scale in centi-
meters is made from the top of the right-hand tube (Fig. 84, No. 8).
This ruling, or gauge, should be about 15 centimeters long. Extend-
ing from the right extremity of the U-tube is a small rubber tubing
which is attached to the chamber containing the injection fluid;
and extending from the inferior part of this chamber is another tub-
ing which has the injection needle attached to the free end.

The injection should be done under 120 millimeters pressure.
The stop cock of the pressure chamber is released sufficiently to
raise the mercury in the U-tube six centimeters, which multiplied
by 2, the amount of work required to raise two columns, makes 120
millimeters pressure. If this pressure be maintained, all vessels
should be injected without rupture. The same process may be used
in injecting the air cells through the trachea.

The injecting material may consist of one part finely sifted plaster
of Paris, four parts water, and sufficient gentian violet to make a
violet color. For the coloring, red aniline may be used in preparing
this material. The dye should be dissolved in the water to be used
in making the injection liquid. Caution must be used and the
work rapidly done, as the plaster soon sets, or becomes solid, in the

346 ANATOMY OF THE DOMESTIC FOWL

needle or in the tubing. A small cannula should be used, since
the endothelial lining of the arteries are easily injured and diffi-
culty may thus be created.

_ Select for arterial dissection an old cock, as in a bird of this kind
the arteries are larger and the difficulties are reduced. Select for
bleeding and injection the ischiadic artery in the thigh region. With
the sharp point of the thin blade of a knife make an incision length-
wise of the artery being careful not to strip back the endothelial
lining of the artery. Allow as much of the blood as will escape
before injecting; in fact, the arteries should be thoroughly emptied,
so that there is no longer danger of a clot’s plugging some vessel
and thus preventing its filling. Since the blood of most birds coagu-
lates in about thirty seconds, this work must be done rapidly, care
being exercised to keep the flow running as long as possible. After
bleeding is completed, insert the cannula and tie the vessel tightly
around the cannula to prevent the escape of the injecting fluid. See
that all connections are sufficiently tight to prevent the escape of
liquid under pressure. After the injection is completed, remove the
cannula and tie the artery with a small twine, preferably cotton.
Quickly remove all injecting fluid from the needle, the tubing, and the
injecting chamber.

During the operation of bleeding the cock may be chloroformed,
care being taken not to administer chloroform to kill him; for it is
necessary to maintain life as long as possible so that the heart may
be kept beating and all blood possible drained from the arteries.
After the injection is completed the bird may be plucked and im-
mersed in the preservative fluid in the same manner as in the
preparation for dissection for muscles.

The arteries, the veins, and the nerves may now be dissected and
studied in relation to one another and in relation to the muscles,
the bones, and other structures. The skin should not be removed
from the shanks till it is desired to dissect these parts, as the tissues
quickly dry out. In fact, the tendons of the shanks and toes can
best be dissected while the specimen is fresh.

A Study of the Structure of Bones.—Longitudinal and transverse
sections of old bone may be made by making thin longitudinal and
transverse sections with the bone saw, and then by making them
very thin with a fine three-cornered file. Examining under the
low power microscope, we note the lacune, the canaliculi, and the
Haversian system.

OUTLINE FOR LABORATORY STUDY OF THE CHICK 347

Similar sections in green bone may be studied if prepared as
follows. Secure specimen of bone just removed from a fowl and
place it for three days in a 10 per cent. aqueous solution of hydro-
chloric acid. Test by puncturing with a needle, and, if all the
mineral salts are removed, place in a water bath and wash for four
hours. Pass it through the fluids usually employed in preparing
specimens for sectioning with the microtome. Stain as sections of
other tissue for microscopic study. See the description below. If
the ends of the bone be included, it will enable the student to study
not only compact bone but also cancellated bone and articular, or
hyaline cartilage, and in some of the bones, as the femur, the red
marrow.

Special Technic for the Dissection of Cranial and Spinal Nerves.—
It is rather difficult to dissect the cranial and spinal nerves of the
fowl, owing to the fact that the structures are very small. The
bone is rather hard and the nerve tissue so delicate that great skill
must be attained to achieve any degree of success.

A simple technic has been developed as follows: Place the head
and neck, or other structures of the spinal column in a 10 per cent.
aqueous solution of hydrochloric acid for three or more days, the
time depending on the size of the specimen and the amount of soft
structures surrounding it. This solution removes all the calcium
salts from the bone and makes the removal of the bony structures
a less difficult task:

Directions for the Study of Soft Structures.—Secure a specimen of
the tissue to be studied—lung, muscle, intestine, liver, pancreas—
from a normal fowl just killed. The specimen should be not more
than 14 inch square. After first hardening three days in 10 per
cent. formaldehyde. Pass through the following fluids:

1. Alcohol, 95 per cent................---55. 24 hours
2. Alcohol, absolute...................--005. 24 hours
3. Alcohol and ether, equal parts............. 24 hours
4. 1 per cent. celloidin............. Seni y, ee ae 24 hours
5. 2 per cent. celloidin....................--. 24 hours
6. 4 per cent. celloidin...............-...-04. 24 hours
7. 6 per cent. celloidin...........0.......-0.. 24 hours!
8. 10 per cent. celloidin. . ieee seeeee. 24 hours
g. Place on block, and as soon as 5 solid, place in 80 per cent. alcohol

until ready to section. Histoloid or parlodion will take the place
of celloidin.

348 ANATOMY OF THE DOMESTIC FOWL

In placing specimen on the block be careful that the specimen lies
conveniently for cutting the sections in the right direction. As soon
as the surface has hardened a little, add a few drops of thick celloi-
din, and repeat until there is a good body of celloidin. Allow to
stand until the tissues are quite firmly fastened to the block, but
not long enough to permit shrinking. Then place in 80 per cent.
alcohol until the specimen is perfectly firm, 12 or more hours, be-
fore cutting.

All tissues, cut sections, and mounted blocks are to be placed in
80 per cent. alcohol. As containers for this purpose shell vials will
be most handy.

Cut the sections with the microtome as thin as possible, the
thinner the better. The following process of staining will make the
nucleus blue and the cytoplasm reddish.

. Float section in a tumbler of tap water.

. Place section on slide, and immerse in hematoxylon for five toten minutes.
. Immerse in acid alcohol from two to five seconds.

. Place on slide, and immerse in eosin from one-half to three minutes.

. Wash thoroughly in alcohol.

. Clarify in oil of cloves, oil of cedar, or beechwood creosote, ten minutes.
. Mount in balsam.

9. Label and study.

COMI DNwW bv

Delafield’s hematoxylon is prepared as follows:

Hematoxylon crystals.................000. 4 grams
Alcohol, 95 per cent................0.0000. 25 C.C.
Saturated aqueous solution of ammonia alum. 400 c.c.

Add the hematoxylon dissolved in the alcohol to the alum solu-
tion, and expose in an unstoppered bottle to the light and air for
three or four days. Filter and add:

GIYVCelMnas sce tenancies meee l ee eat oeen 100 C.C.
Alcohol, 95 per cent..............0..2000005 LOO C.C.

Allow the solution to stand in the light until the color is sufficiently
dark; then filter, and keep in a tightly stoppered bottle. The
solution keeps well and is extremely powerful. So long as it is good
the solution has a purplish tinge. If time permits, it would be wise
to combine the alum, the hematoxylin, and the water, and to ripen
the solution for two or three weeks before adding the other ingredi-
ents, which have a tendency to prevent oxidation.

OUTLINE FOR LABORATORY STUDY OF THE. CHICK 349

The acid alcohol is made as follows:

Absolute alcohol............... 000000 ee eee 70 C.C.
Distilled water................. chia elas ere 30 C.C.
Mix.

Above solition.........0....00cccceveeees 99 C.c.
Hydrochloric acid.............00....000000. IC.c

Eosin is sold in two forms, that soluble in water and that soluble
in alcohol. The eosin soluble in water is preferred, because with it.
a greater degree of diffusion in stain can be obtained.

Keep on hand a saturated aqueous solution and dilute with water
as needed. The strength of the solution to be used varies somewhat
with the tissue and the reagent in which it is to be fixed; but usually
the strength should be between 149 and 14 per cent. when eosin is
used after hematoxylin. The diluted solutions should contain 25
per cent. of alcohol, otherwise they will not keep well. When eosin
is used before an analine dye, such as methylene blue, a 5 per cent.
or even a saturated solution should be used.

To Stain Sections of Liver for the Study of Kupffer Cells.— To bring
out this reaction Keys suggests the following technic:

Fix small blocks of the fresh tissue of spleen or liver for
eighteen to twenty-four hours in Miiller’s fluid plus 5 per cent.
mercuric sublimate. Imbed in paraffin and section to 4 microns.
Fix sections to slide, and stain twenty to forty minutes with acid
carmine. Wash, and transfer to equal parts of a 2 per cent.
aqueous solution of potassium ferrocyanid and of a 2 per cent.
aqueous solution of hydrochloric acid. Remove after three to ten
minutes, wash in distilled water, and pass quickly through a 0.5
per cent. aqueous erythrosin solution. Dehydrate in alcohol, clarify
in xylol, and mount in Canada balsam.

To Prepare Anatomical Specimens for a Museum.—The
Keiserling method gives the best results, since by this method the
tissues retain their normal color. The three steps are as follows:

1. Place the specimen in the following solution and leave from
one to seven days, the length of time depending upon the size of the
specimen.

POrMalini: <.ndicsdcgeecuicnnyeeaee weacee wens 200 C.C.
Potassium acetate......................... 30 grams
Potassiummitrated.y scueakvecnssiee ee aeaes I5 grams

Watetia cc sca. cede tg wane eens Chee aan ed 1000 C.C.

350 ANATOMY OF THE DOMESTIC FOWL

2. Pass the specimen through each of the following solutions,
leaving it in each twenty-four hours or until the normal color is
obtained. The specimen should be removed from alcohol as soon
as color is attained. If it is left in the alcohol too long it will
again lose some of its color.

AlcOhol eid icine? yas Bebecing ie SO Vacs seed ck 40 per cent.
Al coh Ol\yeunmis avaa weteen seers bens pee oes 60 per cent.
Alcoholism vious yoke yams ahecta ced eaetece eet 80 per cent.
AL GODOM iasen ai fuss 2.5 cs esha cinta aude ea Dae ood full strength

3. Place the specimen in the following permanent solution, label,
and place in museum.

GIy Cerin». seas dodanie ba an Whee a te wees -. 40C.C.
Potassium acetate..............-......000. 40 grams
Distilled water...............020-.008000- 400 C.C.

A small piece of thymol must be placed on the top of the liquid
in each jar, or mold will develop and spoil the specimen.

To Make Specimens Transparent.—Specimens may be rendered
transparent by the method of Spalteholz.

The steps are essentially as follows:

I. Preparation of the fresh tissue. If any parts are to be made
conspicuous, as blood-vessels, or the lymphatic system, they must
be injected with an insoluble, unbleachable substance. Spalteholz
recommended carmine or methylene blue, and carbon. I have
found Higgin’s ordinary black carbon ink excellent for this purpose.
The system or systems are injected with this substance while the
tissue is perfectly fresh.

II. Fixation. The tissues are fixed preferably in 10 per cent.
formaJin. The length of time for fixation depends on the size of
the tissue. In formalin it requires from eight hours upward to fix
completely.

III. Rinsing. Running tap water for five or ten minutes accom-
plishes the rinsing. If it is impracticable to pass directly into the
bleaching fluid, the tissues may be kept temporarily in 60 per cent.
or 70 per cent. alcohol. They should then be rinsed again thoroughly
in water when ready to bleach.

IV. Bleaching. The bleaching fluid used is hydrogen peroxid
to which ammonia is added until a white precipitate forms. The
proportion is approximately two parts of peroxid and one of
ammonia. The material is bleached until all the color is removed

OUTLINE FOR: LABORATORY STUDY OF THE CHICK 351

‘and the tissue looks perfectly clear or slightly opaque. It may be
quite transparent as the protein coagulate is somewhat white, but
all yellow or reddish color should be bleached away.

V. Washing. Rinse thoroughly in running tap water or through
several changes of water until the odor of ammonia is quite gone.

VI. Dehydration. Pass gradually through alcohol solutions, 30
per cent., 50 per cent., 60 per cent., 70 per cent., 80 per cent., 95
per cent., and last through absolute alcohol. The time required
for dehydration will vary with the size of the material, but in either
95 per.cent. solution or in absolute alcohol the tissue should remain
until well hardened, twenty-four hours or more. Dehydration is
completed by passing from absolute alcoho], to a fluid one-half
absolute alcohol and one-half benzol; thence for a few days to pure
benzol.

VII. Clarifying. From benzol the material is finally clarified
in winter-green oil or any other standard clearer, and put up in its
final position in the museum jar.

In commenting on this method Dr. A. F. Contant says: “I have
found this to work very successfully in the injection of the lympha-
tics of the human skin, which, as you know, is a rather delicate
injection and has been difficult of demonstration by other methods.
With this method, however, I have prepared whole portions, as the
side of the face, the leg, etc., of small animals and embryos which
show clearly the whole course of the lymphatic vessels and nodes, in
situ, and their relations to surrounding parts.”

EQUIPMENT FOR THE DISSECTION LABORATORY

Figure 84 illustrates some essential equipment for the dissection
laboratory. The equipment should consist of a pump, No. 1, which
forces air through the rubber tube, No. 2, into the pressure tank, No.
4, which is guarded by the valve at No. 3. At dial, No. 5, indicates
the pressure of the air within the tank. The air as needed is re-
leased through an outlet valve. The air now passes through the
rubber tube, No. 6, into the left arm of the manometer at No. 7.
The manometer is simply a glass tubing filled with mercury to the
point indicated at No. 7. By the side of the opposite arm there is
made a scale graduated in centimeters. The tube at No. 9 being
attached to the Y-tube, conveys air under the same pressure into
the injection chamber as that supporting the column of mercury

aes ANATOMY OF THE DOMESTIC FOWL

of the manometer. It is necessary to have a pinch cock, as indi-
cated at No. 11, to control the liquid within the tube. No. 12
illustrates the tube in the end of which, No. 13, there is inserted a

se . » a F as aes nT

cg we” © BA

Fic. 84.—Photograph showing injection apparatus, dissection instruments,
dissection pan and death chamber.

1, Pump. 2, Rubber tube leading from pump to compression chamber. 3,
Stop cock. 4, Compression air tank. 5, Pressure indicator. 6, Rubber tube
leading from pressure tank to manometer. 7. Top of mercury in manometer
tube. 8, Open end of glass tube showing scale in centimeters. 9, Tube lead-
ing from 4 to injection chamber. 10, Injection chamber containing injection
fluid. 11, Pinch cock on rubber tube connecting injection chamber with.injec-.
tion canula. 12, The tube. 13, Injectioncanula. 14, A metal dissection tray.
15, Death chamber. 16, Base of same. 17, Rubber tube connecting gas cock
with death chamber. 18, Bone saw. 19, Bone cutter. 20, Scapula. 21,
Tenaculum. 22, Forceps. 23, Straight scissors. 24, Small pair of curved
scissors.

trocar which is introduced into the artery and tightly tied with a
cord.

A convenient dissection tray may be made from galvanized iron.
It should be 16 inchessquare and about 1 inch deep (Fig. 84, No. 14).

OUTLINE FOR LABORATORY STUDY OF THE CHICK 353

A death chamber is made by using a bell jar 12 inches in diameter
at the bottom. This is used on a perfectly smooth beard 16 inches
square. Through the center of this board is inserted a glass tube
3g inch in diameter. To this glass tube is attached a rubber tube
the other end of which is attached to a gas jet.

The instruments needed in dissecting are illustrated in Fig. 84.
No. 18 is a bone saw; No. 20 is a scalpel; No. 21 is a tenaculum; No.
22 isa pair of forceps; No. 23 is a pair of straight scissors; and No. 24
is a small pair of curved scissors.

BIBLIOGRAPHY

Baum AND ELLENBERGER, Handbuch der Vergleichenden Anatomie, Berlin,
1912.

Barrows, H.R., Me. E. S. Bull. 232, pp. 16, plates 6, 1914.

BRADLEY, O, CHarnocx, The Structure of the Fowl, pp. 146, illustrations 73.

Cuaveav, A., Comparative Anatomy of Domestic Animals, New York, 1893.

Curtis, M. R., Ligaments of the Oviduct of the Fowl, Me. E. S. Bull. 206, 1910.

DouvaL, ——————_-, Atlas of Embryology.

FostER AND BALFour, Elements of Embryology.

Gapow, H., AnD SELENKA, E., Végel. I. Anatomischer Theil (Dr. H. G.
Bronn’s Klassen und Ordnungen des Thier-Reichs, Sechester Band, Vierte
Ahtheiburg), Leipsig, 1891.

Gray, Henry, Anatomy Descriptive and Surgical, New York, 1908.

Heister, J. C., Embryology, Philadelphia, 1901.

Kavupp, B. F., Male Reproductive Organs of the Fowl, Am. Jr. Vet. Med.,
vol. X, II, 2.

Kauvpp, B. F., Female Reproductive Organs of the Fowl, Am. Vet. Rev., vol.
49, IT, 4.

Leisering Atlas of Anatomy, edited by W. ELLENBERGER, translated by A. T.
Peters, Chicago, 1905.

Lr14m, F. R., Embryology of the Chick, Chicago, 1906.

Owen, R., Comparative Anatomy and Physiology of Vertebrates, London,
1866,

_ Scumetsser, H. C., A Study of the Blood of Fowls, Johns Hopkins Hospital,
TQI5.
Oe R. W., Myology of the Raven, pp. 318, illustrations 76, London,
t8go.

Strangeways’ Veterinary Anatomy, edited by I. VaucHan, Edinburgh, 1892.

SurFACE, F. M., Histology of the Oviduct of the Fowl, Me. E. S. Bull., 206,
IgI2.

23

INDEX

ABDOMINAL air sac, 202
cavity, 156
Abducens nerve, 270
Abductor minimi digiti muscle, t10
Accessorius spinalis nerve, 274
Accessory organs of digestion, 152
Acetabulum, 48
Achillis tendon, 69
Acoustic lamina, 323
nerve, 306
vesicle, 322
Adductor longus muscle, 117 - F
magnus muscle, 117
Adrenal gland, 191
Adventitia, 201
Afferent. nerves, 300 -
Air-sacs; 199, 325°
abdominal, 202.
anterior diaphragmatic, 202
thoracic, 200
cervical, 201
femoral extensions, 203
humeral extension, 200
posterior diaphragmatic, 202
subpectoral prolongation, 200
subscapular prolongations, 200
suprarenal extensions, 203
Ale cinerez, 291
orbitale, 28
temporales, 29
Albumin, 180
portion of oviduct secreting, 185
Allantois, 321
Alula, 311
Alveolar glands, 141
nerve, 270
Amnion, 320, 327
Ampulle, 306
Ampullar dilatations, 322
Anapophyseal ridge, 38

355

Anatomic specimen, preparation of,

349
Anconeus muscle, 107
Angiology, 206
Angular glands, 141
groove, 52
Annular ligament, 58
Annulus fibrosus, 58 :
Anterior coracobrachialis nerve, 284
diaphragmatic air-sac, 202
fossa, 25 '
thoracic nerve, 284
Aortic arch, 325
bulb, 324
Aponeurosis, 59
Apparatus, circulatory, 206
digestorius, 135
respiratory, 193
uro-genitalis, 169
vocal, 195
Appendages, structure of, 309
Appendico-costales muscle, 99
Appendicular skeleton, 13
Apteria, 34
Aqueduct of Sylvius, 268, 289
Arachnoid, 288, 289
Arbor vite, 291
Arch, hemal, 38 ;
scapular, 40
Area opaca, 332
pellucida, 332
vasculosa, 332°
Arteria cerebri profunda, 217
Artery or arteries, 209, 325
acromial, 222
anterior circumflex humeral, 222.
vertebral, 221 :
aorta, 211
auricular, 220
axillary, 222

356 INDEX

Artery or arteries, basilar, 217 Artery or arteries, mesenteric, 227

brachialis, 222

brachio-cephalic sinister, 212

bronchialis, 215

carotid trunk, 215

carotis cerebralis, 215
communis, 215
externa, 215

celiac. axis, 226

cerebral, 217

cerebri profunda, 217

cervicalis ascendens, 221

circumflex femoris, 228

clavicular, 222

coccygeal laterales, 232

collateralis radialis, 223

common aorta, 211

coronary, 209

crural, 228

esophageal, 224

ethmoidal, 218

ethmoidales externa, 218

external facial, 220
thoracic, 222

facial, 220

femoral 228

hemorrhoidalis intima, 232

hepatica dextra, 227

hyoid, 218

iliac, 229

inferior cerebellar, 217
esophageal, 215
thoracic, 222

intercostal, 224

internal alveolar, 220
ethmoid, 218
facial, 220
mammary, 222
maxillary, 220
ophthalmic, 217
pelvic, 228
thoracic, 222

lacrimalis, 217

lingualis, 220

lumbar, 225

median coccygeal, 232
hemorrhoidal, 227

meningeal, 216

muscularis, 207

occipital, 216

occipitalis profunda, 216
sublimis, 216

ophthalmica externa, 216

ovarian, 226

plexus palpebralis, 217
temporalis, 216

posterior aorta, 224
circumflex humeral, 223
mesenteric, 227
vertebral, 221

profunda communis, 231
penis, 232

pudenda externa, 232

pulmonalis dexter, 213
sinister, 213

pulmonary, 213

radial, 223

ramus anterior, 217
-posterior, 217
profundus, 209
superficialis, 209

recurrent ciliaris posticus, 217
ilio-celiacus, 227
intestinalis, 227
renalis, 229
sinister, 227
superior hemorrhoidal, 227
ulnar, 223

renal, 226

tetine centralis, 217

sacralis media, 229, 232

spermatic, 226

sphenoid, 217

spheno-mazxillaris, 217

splenic, 227

sternal, 222

sterno-clavicularis, 221

subclavian, 212

subcutaneous colli, 215

subscapular, 222

superior cervical, 215
laryngeal, 218

sylvian, 217

temporal, 216

thoracic, 222

Artery or arteries, thyroid, 215

tibialis antica, 230
postica, 230
wnar, 223
umbilical, 228
vertebral, 215
Arthrology, 56
Articulo-jugale, 58
Arytenoid cartilage, 194
Atlas, 37
Auricle, 324
Auricular appendage, 208
meatus, 305
ossicles, 305
ventricular valve, 207
Axial skeleton, 23
Axillaris nerve, 23
Axis, 37
cylinder process, 277
Axolemma, 277
Axone, 277
hill, 277

BarBES, 310
Barbules, 310
Basi-branchial bone, 35
Basi-hyal bone 35, 36
Basilar artery, 217
Beak, 139, 310, 316
Biceps band, 114
brachii, 104
flexor cruris, 113

Biventer cervicis muscle, 77, 83

Blastema, 322°

Blastoderm, 318

Blood, 257
coagulation, 260
composition, 260
formation, 260
function, 257
plasma, 260
reaction, 257
vascular system, 206
vessels, 209

Bloom, 188

Bone or bones. 17
atlas, 37
axis, 37

INDEX

Bone or bones, cancellous, 18

carpus, 44, 47
classification, 20
compact, 17
composition, 21
cervical vertebre, 35, 37
coccygeal, 35, 41
dorsal vertebrz, 35, 39
entoglossal, 35
ethmoidal, 23, 27
femur, 50

fibula, 53

flat, 2

frontal, 23, 29
furculum, 24.
growth, 20
humerus, 44, 45
hyoid, 35, 36

ilium, 49

inferior maxilla, 23, 34
irregular, 21
ischium, 49

jugale, 23, 31, 33
lacrimal, 23, 31, 33
long, 20
lumbo-sacral, 35, 39
maxille,.23, 31, 32
metacarpus, 44, 47
metatarsus, 53
nasal, 23, 31, 32
occipital, 23, 35

of cranium, 23

of face, 31

of fore limb, 44

of hind limb, 50

of pelvis, 48

of shoulder, 43

of skull, 23

of thorax, 42

of vertebre, 26
palatine, 23, 31, 33
parietal, 23, 29
phalanges, 44, 47
premaxilla, 23, 31
pterygoid, 23, 31, 33
pubis, 50
pygostyle, 24
quadrate, 23, 34

357

358
Bone or: bones, quadrate-jugale, 23,
33 36
radius, 44, 46
ribs, 41
scapular arch, 40
sesamoid, 54
sphenoid, 25, 28
supplied with air, 204
tarsus, 53
temporal, 23, 29
tibia, 52
turbinated, 34, 193
ulna, 44, 46
vomeral, 23, 31, 32
zygomatic, 23, 31, 32
Bowman’s capsule, 171
Brachial nerve plexus, 282. -
Brain, 288
ale cinerez, 291
anterior commissure, 296
aqueduct of Sylvius, 289
arbor vitz, 291
calamus scriptorius, 290
cerebral peduncles, 291
choroid plexus, 296
corpora restiformia, 289
corpus callosum,.296 .
striatum, 296
coverings, 288
crura cerebelli, 291
cerebri, 289
fore, 290 i
fourth ventricle, 290
hind, 290 "
hippocampus, 297
hypophysis, 289
inferior pyramids, 291-
Jamina terminales, 295
lateral ventricles, 297
medulla oblongata, 290
mid-, 290
nervi amygdales, 296
optic chiasm, 289
lobes, 289
pars commissuralis, 289
pons varolii, 289
processus cerebri mammillares, 297
pyramidal columns, 291 .

INDEX

Brain, ‘sulcus centralis, 291
superior pyramids, 291-.
thalami optici, 289 ~~ —--
tubercula olfactoria, 297
valve of Vieussens, 290 «
ventricles, lateral, 267° -

Bronchi, 193, 197
diaphragmatic, 197 .

Bronchial artery, 215
tubes, 197

Bronchialis anticus, 89, 105
longus inferior nerve, 284

superior nerve, 283
posticus, 89

Broncho-trachealis anticus, 38
brevis, 89

Brunner’s glands, 149

Bulla tympaniformis, 195

Bursa of Fabricius, 152

CCA, I51
Calamus, 310
scriptorius, 290
Canal or canals, caroticus ‘et jugulare,
27
Haversian, 17
hypotarsal, 53
ilio-lumbalis, 48
neural, 38
of Petit, 305
urinary, 170
Volkmann’s, 17
Canaliculi, 17
Cancelli, 17
Capillaries, 209
Capsular ligament, 57
Caput costz, 42
Carotid trunk, 215
Carotin, 314
Carotis cerebralis artery, 215 :
communis, 215
externa artery, 215
Carpi radiale, 47
ulnare, 47
Carpus, 44, 47
Cartilage semilunaris, 69
Cavity, cotyloid, 49
glenoid, 44

Cavity, glenoidalis interna, 67
nasal, 35
sigmoid, 46
Cavum cranii, 23
ilio-lumbale dorsales, 48
- Celiac axis, 226
Cera, 310
Cerato-branchial cartilage, 35
Cerato-glossus muscle, 807
Cerato-hyoideus muscle, 80
Cerebellar cortex, 293
Cerebellum, 25, 295
Cerebral lobes, 322
peduncles, 291
Cerebro-spinal axis, 288 . .
nervous system, 265
Cerebrum, 25
Ceroma, 37
Cervical air-sac, 201. .
, artery, superior, 215
nerve ganglion, 270

sympathetic nerve ganglion,. 27 5

vertebra, 35, 37
Chalazz, 180
Chamber, nasal, 193
Chorion, 321, 327.
Choroid coat, 323
Choroidea, 303
Chromophilic bodies, 280
Chromosomes, 318
Ciliary ganglion, 271
nerve, 304
process, 304, 323
Circulatory system, 206 |
Circumconcha muscle, 128
Circumduction, 57
Clavicle, 44
Clavicular artery, 222
Claws, 310
Cleido-trachealis muscle, 15
Cloaca, 151
Clothing feathers, 310
Coccygez laterales arteries, 232
vertebre, 35, 41
Cochlearis, 305
Collum costae, 42
Color of skin, 314
Columella, 31, 305

INDEX

359.

Column, vertebral, 35
Columne carne, 207
Complex nerve ganglion, 271
Complexus muscle, 8:
Composition of bone, 21,
of egg, 181 a
Condyle, external, of femur, 50
inner, of femur, 51
Conjunctiva, 303 ;
Constrictions of Ranvier, a77
Coprodeum, 151
Coraco-brachialis muscle, 103
Coraco-humeralis muscle, ror
Coracoid bone, 194
Corium, 313
Cornea, 323
Corneum, 309
Cornu, hyoid, 35
Coronary artery, 209
Corpora restiformia, 289
Corpus ciliare, 303
Costal bronchial tubes, 197
process of sternum, 24: .
Cotyloid cavity, 65
Course of food, 152
Cranial cavity, 23
Cranium, 23
Cricoid, 194
Crico-trachealis ligament, 194
Cristiilii, 48
sterni, 42
Crop, 142
Crura cerebelli, 291
cerebri, 289
Crural artery, 228
nerve plexus, 285

Crystalline lens, 303, 304, 305, 322,

323 ©
Cuneiform bone, 46
Cutaneous brachii superior nerve, 283

follicle, 323
Cutis, 313

DEGLUTITION, 143
Deltoid, 104
Dendrites, 297 :
Depressor caudz muscle, 95
coccygis muscle, 95

iN

360

Depressor glossus muscle, 80
palpebre inferioris, 125
Derivatives of germ layer, 342
Dermis, 313
Dermo-cleido dorsalis, 75
Dermo-dorsalis, 72
Dermo-frontalis, 72
Dermo-humeralis, 72
Dermo-iliacus, 75
Dermo-pectoralis, 73
Dermo-spinalis, 75
Dermo-temporalis, 73
Dermo-tensor patagii, 72
Dermo-ulnaris, 76
Diaphragm, 165
Diaphragmatic bronchial tubes, 197
Diapophysis, 38
Digastric muscle, 78
Digestive apparatus, 135
Digits, 54
Dissection, 343
laboratory, 351
of arteries, 345
of bone, 346
of muscles, 343
of nerves, 347
of viscera, 344
Division of skeleton, 22
Dorsal ligament of oviduct, 188
vertebre, 35
Dorso-cutaneous nerve plexus, 283
Ductless glands, 148, 329
adrenal, 191
parathyroid, 191
spleen, 155
thymus, 190
Ductus arteriosus, 325, 329
Botalli, 214
Duodenum, 148, 150
Dura mater, 288

Ear labyrinth, 305
Ectoderm, 320
Efferent nerves, 300
Egg, 180
composition, 181
tooth, 327
Embryology, 318

INDEX

Endocardium, 206, 207, 208
Endolymph, 306
Endothelium, 206
Entoderm, 320
Entoglossal bone, 35
Entotympanic, 77
Epicondyloid fossa, 52
Epidermis, 176, 207, 313
Epididymis, 176
Epineural appendage, 38
Equipment, 351
Erythrocytes, 258

fate of, 261

“Esophageal artery, 224

inferior, 215
Esophagus, 142
Esthesiology, 303
Ethmoid bone, 27
Eustachian tube, 29, 136
Extensor annularis brevis muscle,
I21
brevis digitorum muscle, 120
digitorum communis muscle, 106
femoris muscle, 113
hallucis brevis muscle, 119
indicis longus muscle, 108
longus digitorum muscle, 119
metacarpi radialis longior muscle,
105
ossis metacarpi pollicis muscle, 107
proprius pollicis muscle, 109
External facial artery, 220
thoracic artery, 222
Extremitas vertebralis, 42

Fasrictvs, bursa of, 152
Facial artery, 220
Falx cerebri, 289
Fasciculi, 70, 71
deep, 71
superficialis, 71
Feathers, 311
alula, 311
coverts, 311
primaries, 311
rectrices, 311
rudder, 41
scapularies, 311

INDEX

Feathers, secondaries, 311 Foramen nutrient, 52
tertiaries, 311 oblongum, 24
Female generative organs, 178 optic, 27
Femoral artery, 228 ovale, 306, 207, 329
Femoro-caudal, 114 pneumatic, 42, 43, 45
Fenestra ovalis, 31 triossium, 44, 61
rotunda, 31 Fore brain, 290
vestibularis, 105 limb, 44
Fertilization, 318, 319 Fossa anterior, 25
Fetal circulation, 329 articularis transversa, 54
Fibers of Sharpey, 20 cranii media, 25
Fibrin ferment, 261 posterior, 25
formation, 261 epicondyloid, 52
Fibrinogen, 261 epitrochlear, 51
Fibrino-globulin, 261 intercondyloid, 51
Fibular bone, 53 middle, 25
ridge, 52 ovalis, 207
Fifth cranial nerve, 268 pneumatic, 45
inferior maxillary division, 268 posterior, 25
ophthalmic division, 268 subcondyloid, 27
superior maxillary division, 268 trochanteric, 50
Filiform papille, 41 Fourth ventricle, 290
Filo-plume, 311 Fovea cardiaca, 324
Flesh, 70 ischiadica, 48
Flexor brevis pollicis muscle, 109 lumbalis, 48
capitis inferior muscle, 82 pudendalis, 48
carpi ulnaris brevior muscle, 109 Fowl skeleton, 21
muscle, 108 Frontal bone, 29
digitorum profundus muscle, 108 Function, centers of, 301
sublimis muscle, 108 muscles of, 128
hallucis brevis muscle, 121 Funnel portion of oviduct, 183
longus muscle, 122 Furculum bone, 24
metacarpi brevis muscle, 111
radialis muscle, 106 Gat bladder, 154
minimi digiti muscle, 110 Ganglion, 300
brevis muscle, 110 cardiacum, 299
perforans digitorum profundus mus- cervical, 270
cle, 124 sympathetic, 275
perforatus annularis primus pedis ciliary, 271
muscle, 122 complex, 271
indicis primus pedis, 123 Gasserian, 268
medius primus pedis, 123 geniculate, 271
secundus pedis, 121, 122 inferior cervical, 299
Fontanel, 27 orbito-nasal, 270
Foramen intervertebralis, 39 petrosal, 272
ischiadic, 24, 49 spheno-palatine, 270
magnum, 23 spinal, 276

Monro, 295 structure of, 277

362

Ganglion, superior.cervical, 299

sympathetic, 272
thoracic, 299
vagi radicis, 272
Gastrocnemius muscle, 117
Gemellus muscle, 116
Genio-hyoideus muscle, 79
Genital system, 169
Germ layer, 342
Gland, alveolar, 141
angular, 141
ductless, 190
lacrimal, 303
meibomian, 303
mouth, 141
mucous, 136
oil, 41
pharynx, 141
sublingual, 141
thymus, 190
thyroid, 190
uropygii, 309
Glosso-hyal element, 35 .
Glottis, 194
Gluteus medius muscle, 112
minimus muscle, 112
primus muscle, 112
profundus muscle, 112
Gray matte of cord, 292
Groove, angular, 52
tendonal, 54
Growth of bone, 20

HALiux, 54
Hand, 47
Hard palates,136, 139
Haversian canals, 17
Heart, 206
structure of, 207
ventricles of, 324
Hemal arch, 38
Hemapophysis, 38
Hemophage, 262

Hemorrboidalis intima artery, 232

Henle’s limb, 171
loop, 171
Hepar, 153
Herbst’s corpuscles, 307

INDEX

Hind brain, 290
limb, 50
Hormone, 190
Humerus, 44, 45
Hyoid, 218
arch, 324
bone, 35

Hyoideus transversus muscle, 80

Hypapophysis, 38
Hypocleidum, 24, 44,
Hypoglossal nerve, 274
Hypophysis, 289, 295
Hyporachis, 313
Hypotarsal canal, 53
Hypotarsus, 53

IL1o-LUMBALIS dorsalis, 48
Tlium bone, 49
Immovable joints, 56
Inferior alveolar artery, 220
cerebellar artery, 217
larynx, 193
maxillary bone, 34
pyramids, 291
thoracic artery, 222

tuberculum ossis carpi radialis, 47

Infracoccygis muscle, 96

Infraorbital sinus, 32

Ingluvies, 142

Inner ear, 306 :

Interarticulares muscles, 8

Intercostal arteries, 224
nerve, 285

Intercostales muscles, 98

Internal adhesio cornu antici cartila-

ginis lunate, 67
ethmoidal artery, 218
facial artery, 220
mammary artery, 222
mandibular vein, 237
maxillary artery, 220
ophthalmic artery, 217, 218
pelvic artery, 228
secretion, 190
thoracic artery, 222

Interosseous ligament, 58

Interosseus dorsalis muscle, 110

palmaris muscle, 111

Interspinales muscles, 85
Intertransversales muscles, 86
Intestine, free portion, 150
large, 150
small, 147
Intestinum tenue, 147
Iris, 323, 303, 304
Ischiadic artery, 229
foramen, 49
nerve, 286
Ischium, 49
Isthmus, 186

Jomnts, 56
immovable, 56
mixed, 56
movements, 56

Jugal bone, 23, 31, 33

Jugular vein, 233

KERATO-HYALIN, 314
Kerato-hyoideus muscle, 80
Kidneys, 169

Lacrmat bone, 23, 31, 33
duct, 303
gland, 303
sac, 303
Lacune, 17
Lamelle, 17
circumferential, 17
concentric, 17
interstitial, 17
Lamina perpendicularis, 28
. Lamine terminale, 29
Langerhans, islands of, 303
Large intestine, 150
Larynx, 141
bronchio-trachealis, 194
false, 194
inferior, 193
superior, 193
true, 194
Lateral process, 38
Lateralis caude muscle, 95
coccygeus muscle, 95
Latissimus dorsi muscle, 96
nerve plexus, 282

INDEX _ 363

Leucocytes, 258
basophile, 259
eosinophile, 258
lymphocyte, 259
mast cell, 259
mononuclear, 259
polymorphonuclear, 258
Levator caudze muscle, 93
coccygis muscle, 93
palpebr superioris muscle, 124
scapule muscle, 103
Levatores costarum muscle, 98
Lien, 155
Ligament or ligaments, 57
annular, 58
annulare radii, 61
anterior cruciatum genu, 69
anterius ossis carpi metacarpi et
prime, 69
phalangis digiti secundi, 64
patellar, 67
antero-inferior humero-coracoid-
eum, 61
anticum, 69
articulo-jugale, 58
capsular, 57
capsulare atlantico-epistrophicum
odontoideum, 59
atlantico-occipitale, 58
capituli fibula, 68
cubiti, 61
digitorum pedis, 69
obliquum, 59
ossis tibio-metatarsi, 69
carpi interosseum, 64
radialis internum, 64
claviculo-sternal, 44
coraco-furculare, 61
coraco-humeralis, 61
coraco-scapulare, 61°
inferius, 61
internum, 61
crico-trachealis, 194
cubiti teres, 62
elasticum interspinale profundum,
59
superficiale, 59
externum, 69

364

Ligament or ligaments, extero-laterale
genu, 65
furculo-scapulare, 61
humero-scapulare, 61
ilio-pubic, 65
ilio-sacrale, 65
inferius, 61
internum, 64
intero-laterale genu, 66
interosseous, 58
interosseum, 69
intervertebral, 38
laterale cubiti externum, 61
internum, 61
nuche, 59
obliquo-carpi ulnaris, 62
of carpal joint, 61
of ear, 58
of elbow joint, 59
of finger, 64
of hip joint, 65
of jaws, 58
of knee joint, 65
of liver, 153
of oviduct, 188
of pelvis, 56°
of ribs, 59
of shoulder joint, 59
of sternum, 59
of tibio-metatarsal joint, 69
of toes, 69
of vertebra, 58
ossis carpi radialis internum et
metacarpi, 64
ulnaris externum et metacarpi,
64
internum et metacarpi, 64
pollicare, 64
popliteum, 67
posterior cruciatum genu, 67
posterius, 64
posticum ulnare carpi ulnaris, 63
Poupartii, 65
radiale carpi radialis externum, 64
structure, 57 :
superius, 69
suspensorium corporum vertebral-
ium, 58

INDEX

Ligament or ligaments, suspensorium
dentis epistrophei, 58
tibio-fibulare, 68
transversale commune, 67
transversum, 59
atlantis, 58, 59
externum, 59
triangulare, 59
ulnare carpi radialis, 63
internum, 63
metacarpi externum, 64
internum, 64
Limb, fore, 44
hind, 50
Lingua, 139
Linguales arteries, 220
Lipochrome, 314
Liquor pericardii, 207
sanguinis, 258
Liver, 152, 153
ducts, 155
Longissimus capitis et atlantis, 85
dorsi, 92
Longus colli dorsalis muscle, 83
muscle, 83
posticus muscle, 83
Lumbar arteries, 225
Lumbo-sacral vertebre, 35, 39
Lumbo-sacrales nerves, 285
Lung, 195, 325
tubules, 197, 199
primaries, 197
secondaries, 198
tertiaries, 198
Lymph vascular system, 206, 254
Lymphocytes, 259

’

Matarzis muscle, 125
Male generative organs, 175
Malpighian body, 155, 156, 171
Mandibular arch, 324
Marrow, 20

red, 20

yellow, 20
Masseter muscle, 77
Mast cells, 259
Maxilla, 23, 31, 32
Maxillary arch, 324

INDEX

Median coccygeal artery, 323
hemorrhoidal artery, 227
nerve, 284

Medulla oblongata, 25, 290
ossium. flava, 20

rubrum, 20

Meibomian glands, 303

Melanin, 316 ;

Membrana nictitans, 303, 324
putamine, 329
semilunaris, 195
testacea, 187
tympana interna, 195

Membrane obturatore
brales posteriores, 59

Meningeal artery, 216

Meninges, 288

Meniscus, 56
intervertebralis, 58

Mesentery, 156, 157

Metacarpus, 44, 47

Metasternum, 42

Mid brain, 290

Middle fossa of cranium, 25
meningeal artery, 217

Molting, 313

Motor oculi, 267

Mouth, 135

Movable joints, 56

Mucous glands, 136

Miillerian duct, 184

Muscle or muscles, 70
abductor minimi digiti, 110
adductor longus, 117

magnus, 117
anconeus, 107
biceps, 104

flexor crurus, 113
biventer cervicis, 83

maxille, 77
brachialis anticus, 105
bronchialis anticus, 89

posticus, 89
broncho-trachealis anticus, 88

brevis, 89

posticus, 89
cerato-glossus, 80
cerato-hyoideus, 80

interverte-

365,

Muscle or muscles, ciliary, 304
cleido-trachealis, 75
complexus, 81
constrictor glottidis, 87
coraco-brachialis, 102
coraco-humeralis, ror
deltoid, 104
depressor caudz, 95

coccygis, 95
glossus, 80
dermal, 70, 71
dermo-cleido-dorsalis, 75
dermo-dorsalis, 72
dermo-frontalis, 72
dermo-humeralis, 72
dermo-iliacus, 75
dermo-osseous, 70, 73
dermo-pectoralis, 73
dermo-spinalis, 75
dermo-temporalis, 73
dermo-tensor patagii, 72
dermo-ulnaris, 76
diaphragm, go
digastricus, 78—
entotympanic, 77 _
expansor secundarium, 62
extensor digitorum communis, 106
femoris, 113
indicis longus, 108
metacarpi radialis longior, 105
ossis metacarpi pollicis, 107
proprius pollicis, 107
femoro-caudal, 114
flexor brevis pollicis, 109
capitis inferior, 82
carpi ulnaris, 108
brevior, 109
digitorum sublimis, 108
metacarpi brevis, 111
radialis, 106
minimi digiti, 110
brevis, 110
profundus, 108
gastrocnemius, 117
gemellus, 116
genio-hyoideus, 79
gluteus maximus, 50
medius, 112

366

Muscle or muscles, gluteus minimus,

112
primus, 112
heart, 71
hyoideus transversus, 80
infracoccygis, 96
interarticulares, 85
internal obturator, 49
interosseus dorsalis, 110
palmaris, 11x
interspinales, 85
intertransversales, 86
involuntary, 70
striated, 71
lateralis caudz, 95
coccygis, 95
latissimus dorsi, 96
levator caudz, 93
coccygis, 93
scapule, 103
levatores costarum, 98
longissimus dorsi, 92
longus colli anticus, 84
posticus, 83 ;
masseter, 77
mylo-hyoides, 79
“nomenclature, 71
obliquo-transversales, 82
obliquus abdominis externus, 90
internus, 91
colli, 83
obturator externus, 116
internus 116
of abdomen, 90
of air passage, 86
of anterior pectoral region, 99
of brachial region, 104
of cervical region, 81
of coccygeal region, 93
of costal region, 96
of digit, 109
of dorso-lumbar region, 92
of forearm and hand, 105
of head, 76
of inferior larynx, 86
of pectoral region, 100
of posterior limb, 111
of scapular region, ror
of sternum, 90

INDEX

Muscle or muscles, of superior larynx,

86
of tibial region, 117
of tongue, 79
pectoralis major, 100
secundus, 100
tertius, 100 --
peroneus longus, 118.
platysma myoides, 74
pronator brevis, 107
longus, 107
pterygoideus externus, 78
internus, 78
lateralis, 78
medius, 74
rectus abdominis, 91
capitis anticus minor, 81
lateralis, 84
posticus major, 82
rhomboideus, 17
sacro-lumbalis, 92
sartorius, 111-
scalenus medius, 86
scapulo-humeralis, ror
semimembranosus, 114
semitendinosus, 114
accessorius, 114
serratus magnus anticus, 97
parvus anticus, 97
skeletal, 70, 76
soleus, 118
sphincter, pupillary, 304
sterno-trachealis, 89
stylo-hyoideus, 79
subclavius, 102
subscapularis, 103
supraspinatus, 102
temporal, 76
tensor patagii brevis, 99
longus, 99 :
teres et infraspinatus, 98
minor, 102
thoraco-scapularis, 103
thyreo-arytenoideus, 85
trachelo-mastoideus, 85
tracheo-lateralis, 87
transversalis abdominis, 90
transversus peronei, 94
trapezius, 97

Muscle or muscles, triceps, 104
true dermal, 71
voluntary stridted, 70
Myelon, 322
Myeloncephalus columns, 320
Myocardium, 208

NAILS, 316
Nasal bone, 23, 31, 32

cavity, 35

chambers, 193
Naso-premaxillary process, 324
Nerve or nerves, 264

abducens, 70

accessorius spinalis, 274

acoustic, 271

afferent, 300

alveolar, 270

anterior coraco-brachialis, 284

spinal branches, 281
thoracic, 284

axillaris, 283

brachial plexus, 282

brachialis longus inferior, 284

superior, 283

cells, 280

centers, 300

ciliary, 304

cranial, 265

crural plexus, 285

cutaneous brachialis et inferior

brachialis, 284

brachii superior, 283
dorsal spinal, 281
dorsalis plexus, 282
dorso-cutaneous plexus, 283
efferent, 300
ethmoidalis, 269
facialis, 286
function, 300, 301
furcularis, 286
glosso-pharyngeal, 272
hypoglossal, 27, 37, 274
intercostal, 285
ischiadic, 49, 286
latissimus dorsi, 282
lumbo-sacral, 285
median, 284

INDEX

367

Nerve or nerves, medullated, 277

motor oculi, 267
neurolemma, 277
nonmedullated, 277
obturator, 286
olfactorius, 34, 265
optic, 267

patheticus, 268
peroneus profundus, 287
plexus pedundus, 288
pneumogastric, 273

posterior coraco-brachialis, 284

tamus secundus, 269
recurrent cardiacus, 274
externa, 269
hepatici, 274
infraorbitale, 269
laryngeus, 274
linguales, 273
pharyngeus, 272
pulmonale, 274
subcutaneous, 270
ventralis, 281
thomboideus profundus, 282
superficialis, 282
scapulo-humeralis, 282
serratus plexus, 282
spinal cord, 275
sterno-coracoideus, 284
subcoraco-scapularis, 282
superficialis peroneus, 287
serratus, 282
supra coracoideus, 283
trifacial, 31, 268
ulnar, 284
vagus, 27, 31, 273
group, 273
Nerve-trunks, structure of, 277
Nervous system, 264, 300
Neural arch, 38
spines, 38, 39
Neurofibrils, 280
Neurones, 268, 279
Nostril, 193
Notocord, 322

OBLIQUE process, 39

Obliquo-transversales muscle, 86"

368

Obliquus abdominis externus muscle,

go
internus muscle, 91
dorsalis, 125
inferior, 127
superior, 125 :
ventralis muscle, 121
Obturator externus, 116
internus, 116
nerve, 286
Occipital artery, 215
bone, 23, 25
Occipitale laterales bone, 25
Occipitalis inferius bone, 25
profunda artery, 215
sublimis artery, 215
superioris bone, 25
Odontoid process, 37
Oil gland, 41
Olecranon, 46
Olfactory cavities, 322
cerebral crura, 295
glomeruli, 265
nerve, 265
Odgenesis, 319
Ophthalmic vesicle, 322
Ophthalmica externa, 216
Optic chiasm, 289
lobes, 322, 389
nerve, 267
Orbicularis oculi, 124
palpebrarum muscle, 124
Orbit, 323
Orbital process, 30
Orbito-nasal ganglion, 270
Organ of hearing, 304, 322
of sight, 303
of smell, 307
of taste, 307
of touch, 307
Os angulare, 30
articulare, 30
transversale, 105
Osseous structure, 17
tissue, 17

Ostium tube abdominale, 183

Otocrane, 323
Otoliths, 322

INDEX

Ovarian artery, 226

pocket, 189
Ovary, 325
Oviduct, 182, 325
Ovum, 318

PaLaTAL papillaries, 141

Palatine glands, 141

Palatinus bone, 23, 31, 33

Palatum durum, 139

Palpebral plexus, 217

Pancreas, 152, 155

Papilla, 141

Parapophysis, 38

Parietal bone, 29

Pars commissuralis, 289
glandularis, 143
muscularis, 143
renalis, 251

Partes pedunculares, 294

Patella, 53

Patheticus, 268

Pecten, 303, 323

Pectoralis major, 100
secundus, 100
tertius, 101

Pelvic cavity, 156
girdle, 48

Pericardium, 207

Perimysium, 70

Periosteum, 18

Peritoneum, 156

Peroneus longus, 118
nerve, 287

Pessulus, 195

Petrosal ganglion, 272

Phalanges, 44, 47, 54

Pharynx, 54, 141

Pia mater, 288

Pineal gland, 295

Pituitary body, 25, 289, 295

Placenta, 321

Planum coccygeum, 48

Plasma, 261

Platysma myoides muscle, 74

Pleurapophysis, 38

Plexus, abdominal, 299
anterior splanchnic, 300

Plexus, lacrimal, 217
mesenteric, 299
muscularis, 217
pedundus, 288
Posterior splanchnic, 300
thoracic, 299

Plica primitive, 320

Pneumatic foramen, 42, 43, 45

- Pons varolii, 289

Post-acetabular ridge, 48

Posterior aorta, 224
circumflex artery, 223
diaphragmatic air sac, 202
fossa, 25
nares, 136
orbitalis, 30
vena cava, 247
vertebral artery, 221

vein, 234

Poupart’s ligament, 65

Prezygapophyses, 39

Primaries, 311

Primitive streak, 321

Process, costal, 43
lateral, 37, 39
oblique, 37, 39

of sternum, 42
odontoid, 37
xiphoid, 43

Processus acusticus externus, 31
ciliaris, 304
coracoideus, 44
cubitalis humeri, 45
frontalis, 32

anterior, 32

posterior, 32
furcularis, 43
humeralis, 43
intermaxillaris, 32
ischiadicus, 49
mazxillaris, 32

anterior, 32
odontoid, 37
olecranalis coracoideus, 46
orbicularis, 28,29
orbitalis, 29
palatinus, 32
posterior orbitalis, 30

24

INDEX: 369

Processus uncinatus, 24
zygomaticus, 28, 30

Profunda penis, 232

Pronation, 57

Pronator brevis muscle, 107
longus, 107

Proteids of plasma, 261
of serum, 261

Proventriculus, 143

Provertebra, 320

Pterygoideus externus muscle, 78
internus muscle, 78
lateralis muscle, 78
medialis muscle, 78 ©

Pteryle, 311

Pubis, 50

Pudenda externa artery, 232

Pulmonalis dextra, 213
sinistra, 213

Pulmonary artery, 213

vein, 233

Pulp, 311

Punctum saliens, 320

Purkinje cells, 293

Pyramidal columns, 291

QUADRATE, 34
Quadrato-jugale, 23, 31, 33
Quadratus nictitans, 125
Quill, 310

feathers, 310

RACHIS, 310, 313
Radial artery, 223
Radius, 44, 46
Rami communicantes, 276
glottis, 194
Ramus ascendens ossis ischii, 49
ciliaris posticus, 217
posterior artery, 217
profundus artery, 209
superficialis artery, 209
Rectrices, 41, 311
Rectus abdominalis muscle, 91
capitis anticus minor muscle, 81
dorsalis major muscle, 82
posticus major muscle, 82

370, INDEX.

Rectus capitis ventralis muscle, 82 Sacs, air, 199
dorsalis muscle, 127 Sarcolemma, 70
externus muscle, 127 Sartorius muscle, 111
inferior muscle, 127 Scala tympani, 306
internus muscle, 128 vestibuli, 306 . 7
lateralis muscle, 127 d Scalenus medius muscle, 86
medialis muscle, 128 muscle, 86 : .
superior muscle, 127 Scapho-lunar bone, 47
ventralis muscle, 127 Scapula, 43
Recurrent cardiacus nerve, 274 Scapulo-humeralis muscle, roz
hepatici nerve, 274 . nerve plexus, 282 -
infraorbital nerve, 269 Sclerotic coat, 303, 304
intestinalis nerve, 227 Secondaries, 311
laryngeus nerve, 273 Secretion, internal, 190
lingualis nerve, 273 Semilunar cartilage, 67
pharyngeus nerve, 272 Semimembranosus muscle, 114
pulmonale nerve, 274 Seminiferous tubules, 318
renal artery, 223 Semitendinosus muscle, 114
Ttenales nerves, 229 accessorius muscle, 114
sinister artery, 227 Sense of hearing, 305
subcutaneous nerve, 270 of sight, 303
Red blood cells, 258 of smell, 307
shape, 258 - of taste, 307
size, 259 of touch, 307
structure, 259 organ, 303
Reflex action, 301 Sensory nerves, 300
Renal artery, 226 Septum nasi, 33
corpuscle, 171 Serous cavity, 156
Respiratory apparatus, 193 membrane, 156
Rete malpighii, 313 * sac, 156
Retina, 303, 304, 323 Serratus magnus anticus muscle, 97
Rhomboideus muscle, 97 nerve plexus, 282
profundus nerve, 282 parvus anticus muscle, 97
superficialis nerve, 282 Serum, 261
Ribs, 41 albumin, 261
false, 41 globulin, 261
true, 41 Sesamoid bone, 54
Ridge, ectonemial, 52 Sharpey’s fibers, 20
fibrillar, 52 Sheath of Schwann, 277
post-acetabular, 48 Shell bloom, 188
procnemial, 52 gland, 187
trochanteric, 50 membrane, 181
Rotation, 57 structure, 181
Round ligament, 65 tint, 181
Rudder feathers, 41 Shoulder girdle, 43
. Sinus foraminis occipitales, 240
SACRALIS media artery, 229, 232 fovez hemispherii cerebelli, 241

Sacro-lumbalis muscle, 92 infraorbitalis, 32

INDEX 371.

Sinus longitudinalis, 239
occipitalis, 240.
externus, 240
Petrosus sphenoideus, 240
rhomboideus, 276
semicircularis, 240
temporales, 332
temporo-sphenoideus, 240
transversus, 240
venosus annularis basilaris, 240
Skeleton, 21, 24
appendicular, 43
axial, 22
division, 22
Skin, 309, 323
Small intestine, 147
Smooth muscle, 70
Soleus muscle, 118
Somatic cell, 318
Spermatic artery, 226
Spermatids, 318
Spermatocyte, 318
Spermatogenesis, 318
Spermatogonia, 318
Spermatozoa, 176, 318
Sphenoid artery, 217
bone, 28
rostrum, 29
Spheno-maxillary artery, 217
Spheno-palatine nerve ganglion, 270
Spinal cord, 38
nerves, 281
nervous system, 264
Splanchnology, 135
Splanchnopleure, 327
Spleen, 152, 155
Splenic artery, 227
capsule, 155
pulp, 155
Spur, 54, 317
Squamous epithelium, 137
Sternal artery, 222
Sterno-clavicularis artery, 221
muscle, 284
Sterno-coracoideus nerve, 284
Sterno-hyoideus muscle, 80
Sterno-trachealis muscle, 89
Sternum, 42

Stigmen, 179
Stomach, 143
Stratum corneum, 141, 313, 314
germinativum, 314 .
granulosum, 314
lucidum, 344
Malpighii, 314
Stylo-hyoideus muscle,*79
Styloid process of ulna, 46
Subclavian artery, 234
Subcondyloid fossa; 27 .
Subcoraco-scapularis nerve, 282
Subcutis, 309
Subscapularis artery, 222
Succus entericus, 152
Sulcus ilio-lumbalis dorsalis, 48
centralis, 291, 294
longitudinalis, 291 F
Superficialis peroneus nerve, 287
serratus nerve, 282
Superior laryngeal artery, 218
larynx, 193
median fissure of cord, 276 ..
Pyramidalis, 291
sympathetic ganglion, 272
tuberculum ossis carpi radialis, 47
Supra-coracoideus nerve, 283 :
Sylvian artery, 217
Sympathetic caroticus
208
nervous system, 264, 297
ophthalmic plexus, 298
recurrent cardiacus, 299
temporo-lacrimalis, 298
thoracic trunk, 299
Symphysis ilio-sacralis, 49
ilio-sacri, 49
Synovial apparatus, 57, 156

cephalicus,

TARSO METATARSUS, 53
Tears, 303
Temporal arterial plexus, 216
artery, 215
bone, 29
petrosal portion, 31
squamous portion, 3¢
Temporalis muscle, 76
Tendon Achillis, 69

372°

Tendonal groove, 54
Tensor patagii brevis, 99
longus, 99
tympani, 128
Teres et infraspinatus muscle, 98
minor muscle, 103
Testicles, 175
Thalamus optici, 289
Thorax, 41
Thymus gland, 190
Thyroid artery, 215
gland, 190
Tibialis anticus muscle, 119
Tissue, osseous, 17
Toes, 54
Tongue, 139, 140
Touch corpuscle, 307
Trachea, 194
Trachelo-mastoideus muscle, 85
Transparent specimens, 350
Transversalis abdominis muscle, 92
Transverse fissure, 289
vein, 233
Transversus peronei, 94
Trapezius muscle, 97
Triangularis sterni muscle, 90
Triceps brachii, 104
muscle, 104
Trifacial nerve, 268
Trochanter, 50
Trochanteric fossa, 50
ridge, 50
Trochlea, femoral, 50
True joints, 56
Tuba auditiva, 29, 136
Tuber cinereum et
289
Tuberculum coste, 42
Tuberositas furcularis, 44
humeralis, 44
muscularis, 64
radii, 46
scapularis, 44
Tubuli seminiferi, 176, 318
uriniferi corticalis, 170
Tunica adventitia, 210
intima, 210
media, 210

infundibulum,

INDEX

Turbinate bones, 34, 193
Tympanic membrane, 31

ULNA, 44, 46

Ulnar nerve, 284

Umbilical artery, 228

Umbilicus, 31

Ureter, 174, 187

Urinary apparatus, 169
canals, 170

Urodeum, 151

Urogenital system, 169

Urohyal process, 35.

VaciIna, 187
~ Valve of Vieussens, 290
Valves of veins, 211
Vane, 310
Vas deferens, 175, 178
Vasa vasorum, 211
Vastus externus muscle, 113
internus muscle, 113
Vaxillum, 310
Vein or veins, 233
anterior vertebral, 234
ascendentes laterales, 242
basilica, 246
brachialis, 246
carotes, 241
cava sinister, 245
cave, 233
cephalica posterior, 239
coccygea, 250
colli cutinez, 242
coracoidea, 244
cutinea abdominis femoralis, 250
caudalis, 251
cruralis, 249
pubica, 251
epigastric, 250
esophageal, 243
facialis communis, 238
cutinea, 238
externa, 235
femoralis anterior, 250
interna profunda, 250
foraminis occipitalis, 240
fove hemispherii cerebelli, 241
glandularum thyroidearum. 243

Vein or veins, humeri, 245
hypogastric, 251
intercostales, 244
internal mandibular, 237
intervertebrales lumbalis, 252

sacrales, 249
ischiadic, 252
jugularis, 233
linguales, 242
lingualis et hyoides, 238
longitudinalis, 239
maxillaris, 235
metatarsalis dorsalis interna, 249
profunda, 249
externa, 249
plantaris profunda, 249
occipitalis, 240
externa, 242
externus, 240
of brain cavity, 241
of dorsal region, 243
of fore limb, 245
of head, 235
of hind limb, 248
of neck, 242
of thorax, 244
of viscera, 252
ophthalmica, 236
ovariana, 252
palpebralis, 238
petrosus sphenoideus, 240
pharyngee superiores, 238
poplitealis, 251
posterior vena cava, 247
vertebral, 234
profundus ulnaris, 245
proventricularis communis, 245
inferior, 253.
pudenda, 251
pulmonary, 233
radialis profunda, 245
renales, 249
renalis magna, 252
retis mirabilis temporalis, 237
sacrales, 249
semicircularis, 240
spermatica, 251
sternalis, 244

INDEX 373

Vein or veins, structure of, 211
subclavicularis, 233
subscapularis, 243
suprapalatina, 236
suprarenalis externa, 251

revehentes, 252
surales, 244
temporalis, 238
temporo-sphenoideus, 240
testicula, 252
thoracica externa, 244
interna, 244
tibialis postica, 248
trachealis, 243
transversus, 233, 238
vertebralis lateralis dorsalis, 243

Venous sinuses, 239
trunks, 233

Ventral ligament of oviduct, 188

Ventricles of heart, 324

Ventriculus, 143

Vertebra, 35 _
cervical, 35
coccygeal, 35
dorsal, 35, 39
lumbo-sacral, 35, 39

Vertebral artery, 215
column, 35 y

Vestibulum, 306

Villi, 149

Vitellicle, 321

Vitelline membrane, 180
veins, 324, 327

Vocal apparatus, 195

WIsx bone, 244
Wolffian duct, 184, 339

XANTHOPHYLL, 314

Youk, 180 '
Sac, 327

ZONA opaca, 320
pellucida, 320

Zygapophyses, 38, 39

Zygomatic bone, 23, 31, 33
process, 30

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