600 STRUCTURE AND CLASSIFICATION OP" BIRDS 



springs from the muscular fibres of the accessory femoro- 

 caudal, the other fleshy and springing from the pelvis 

 just behind the acetabulum. It is inserted along the femur 

 below the vastus internus and over the conjoined femoro- 

 caudals. 



In Struthio the rhomboideus superficialis arises, as in 

 carinate birds, from the spinous processes of the vertebrae 

 (1-3 cervicals) ; it is inserted only on to the scapula, The 

 rhomboideus profundus arises from the spinous processes of 

 the last cervical and first dorsal vertebrae ; it is inserted on to 

 the end of the scapula. The serratus superficialis of Stru- 

 thio is a single muscle arising as two or three bands, either 

 from the last cervical and first dorsal rib or, in addition, 

 from the second dorsal rib. It is attached to the ventral 

 border of the scapula. The serratus profundus is divisible 

 into a more superficial and a deeper layer ; the former is 

 the less extensive, and arises either by a slip from the rib ^ 

 of cervical vertebra 19, and by two slips from the last 

 cervical rib, or by two larger slips and one very small one 

 from between the last cervical and the first dorsal rib, and 

 from the latter ; they are inserted on to the inner border of 

 the scapula. The deeper layer also varies, but arises in 

 several slips from the last two cervical ribs. It is also 

 inserted on to the inner border of the scapula. The coraco- 

 brachialis externus is very large as compared with the same 

 muscle in the carinate birds ; it is not quite so large as in 

 Bhea. The coraco-brachialis internus is larger in Struthio 

 than in any other ratite. The biceps arises from the spina 

 coracoidea ; its muscular belly is not well developed ; it is 

 inserted on to the radius and ulna, and on to the membrane 

 between them. As with Bhea the deltoid arises from the 

 scapula and neighbouring region of coracoid. The teres 

 major, again, as in Bhea, is a comparatively large muscle. 



On p. 87 et seq. will be found an account of the muscles of 

 the hand in Palamedea, which I have taken to illustrate that 

 of the carinate birds in general. 



The differences which are to be noticed in Struthio are, 

 apart from minor divergences, the following : — 



