Studies on Avian Anatomy. — II. 
33 
and a fascia connection between this and the posterior border of the 
m. serratns superficialis anterior, which is inserted on the scapula, 
M. serratns profundus consists of three portions. The dorsal bundle 
conies from the free rib at the end of the transverse process; the 
second from the same rib lower down and from its posterior border; 
the third from the posterior border of the following rib. M sub- 
coracoideus arises on the middle third of the median surface of the 
coracoid, aponeurotically from the muscles of that region, partially 
from the neighboring portion of the clavicle. It inserts on the apex 
tuberculi medialis humeri, anterior to the insertion of the m. coraco- 
brachialis posterior and ventral to the m. subscapularis. The muscle 
designated E is the m. coracobrachialis anterior. It arises from the 
lateral anterior end of the coracoid. It inserts on the lateral border 
and on the ventral surface of the humerus, extending down to the 
anterior border of the crista lateralis of the humerus. 
VI. Pterylosis of Geococcyx. 
(Plate VII.) 
The dorsal head feathering begins as a single row median to each 
nostril, then broadens to cover the fore part of the head, becoming 
a single median row back of the eyes. With the two parallel 
rows which arise above each eye it forms a narrow band 
of five rows, which runs back to the base of the head. The 
tract is fairly dense on the side of the head. Around the 
ear is a circle of feathers formed partly by the lower 
one of the two rows arising in front of the eye. Below the ear the 
rows run oblicpiely downward and upward to join, respectively, the 
ventral and dorsal tracts. The feathering of the infra-mandibular 
region consists of a narrow median band which is divided in its pos- 
terior half. The chin and throat are occupied by rows of feathers 
running obliquely from the median line out to the side of the neck 
where they terminate. The ventral cervical tract becomes strong 
toward the base of the neck. The dorsal tract is a broad baud at its 
origin on the nape of the neck, and narrows gradually to end ab- 
ruptly between the shoulder blades. It is renewed on each side of 
this break by a single row which soon becomes strong, and then 
divides to enclose an elliptical apterion. Uniting again it reaches 
its greatest expansion between the insertion of the femora, then grad- 
ually diminishes and terminates near the base of the oil gland. The 
strong humeral tract is continuous with the ventral one. On the 
dorsal surface of the wing is a wide tract covering almost the en- 
