MYOLOGY OP OPISTHOCOMUS CEISTATUS. 361 



The depressor caudce 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 caudce 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 vertebrae 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 caudse 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 caudse interior and externus abduct and flex the tail laterally. The 

 abductor caudse 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 fascice 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 fascise and gluteus externus. The two latter muscles are 



VOL. IX. — PAKT VI. December, 1875. . 3 c 



