MYOLOGY OF OPISTHOCOMUS CRISTATUS. 361 
The depressor caude superficialis.—This is a large, broad, fleshy muscle. It arises 
from the posterior aspect of the slender rod-like pubis, anterior and internal to the 
pubo-coccygeus. It is inserted into the prominent ventral elongated coccygeal tubercle, 
and into the ventral aspect of the bases of the 3rd, 4th, and 5th tail-feathers. By its 
inner border it is in immediate contact with its fellow of the opposite side. 
Depressor caude profundus.—Lies immediately beneath the preceding. It is a broad 
and expanded muscle. It arises from the posterior margin of the sacrum, immediately 
external to the middle line. Its fibres run in a slightly oblique direction backwards 
and inwards, terminating in the median coccygeal tubercle, on its upper aspect, and 
also attaching themselves to the sides and bodies of the transverse processes of the 
coccygeal vertebre situated above the terminal tubercle. Some of the fibres are pro- 
longed on to the bases of all the wing-feathers except the outermost one. Besides these 
muscles there is another one on each side of the median line. It is attached by one 
extremity to the distal end of the coccygeal tubercle, and spreads out into small digi- 
tations to be attached by its other extremity to the bases of the three or four outer tail- 
feathers. The action of this muscle is evidently to approximate the tail-feathers. 
Actions.—The extensors caude superficiales, acting separately and alternately, move 
the tail from side to side. Acting in combination they are powerful extensors of the 
tail. It is these muscles which produce that persistent and over-erect position of the 
tail in birds of the Pheasant-species. In show-fowls I have several times divided these 
muscles to obviate that condition, which is adverse to success in prize-showing. In fact, 
in the highly bred Pheasant-fowl this peculiar and persistent erection of the tail 
considerably militates against the chances of success, as well as detracts from its beauty. 
The abductores caude interior and externus abduct and flex the tail laterally. The 
abductor caude posterior abducts and elevates the tail and spreads the tail-feathers. 
The flexor muscles, acting in conjunction, are powerful flexors of the tail; singly or 
the two of one side cooperating they abduct it to one or the other side. 
The femoro-caudal muscle is large. No peculiarities. 
Muscles of the Leg. 
The Sartorius is long, well developed, and entirely muscular. It arises from the 
anterior extremity and outer margin of the innominate bone. It traverses the thigh 
obliquely, crosses over the knee-joint, and opposite it joins the rectus femoris muscle. 
It is inserted into a tubercle upon the front of the tibia, and into the bone immediately 
below it. 
The rectus femoris is situated immediately behind the preceding. It springs from 
the outer margin of the innominate bone, and from a tendinous aponeurosis common to 
it and the tensor fascie femoris and gluteus externus. It is broad at its origin, but 
diminishes in size as it descends, terminating in a thin flat tendon which abuts on the 
conjoined tendon of the tensor fasciz and gluteusexternus. The two latter muscles are 
VOL. IX.—PART VI. December, 1875. ; SIG 
