292 STRUCTURE AND CLASSIFICATION OF BIRDS 



teres or by at the same time sending a tendinous slip 

 behind it to the scapula. In Arc/us gi.gaiiteus the tendon, 

 running from the elbow, turns round the axillary border of 

 the teres to end by joining a triangular muscular fasciculus, 

 attached by its base to the upper portion of the thoracic 

 surface, which appears to be nothing but a differentiatioii-off 

 of the upper portion of the last-named muscle. In the 

 Crttcidff this insertion into the scapula is also found, but it 

 is tendinous, like the upper element of the thoracic band 

 above described in the storks and Chauna ; and in them 

 there is also a second tendinous slip from the axillary margin 

 of the coraco-brachialis longus (not the brevis) . Iri the Mega- 

 podidse also the attachment to the coraco-brachialis brevis is 

 wanting, the tendon ending either by blending with the teres 

 margin or running on to the scapula.' 



The glutceus primus is a large muscle covering the 

 biceps. Gliitff'its V. appears to be alwa} T s present, but is 

 sometimes (Tliaumalea picta) quite tendinous. 1 



Most gallinaceous birds have the complete muscle formula 

 ABXY + . The femoro-caudal, however, varies in size, 

 and is quite absent in Pavo and Meleagris. It is very 

 slender in Crax and Ortalis.' 2 



The deep flexor tendons belong to type I., and are illus- 

 trated in fig. 54 (p. 100). 



There are two carotids in all but the Megapodes, where 

 the left only is present. A gall bladder is present. 



Some intestinal measurements are given on p. 293. 



The trachea has in a few gallinaceous birds two pairs of 

 extrinsic muscles, thus resembling, it will be observed, the 

 Anseres and Palamedeae. 



Thus in Crax Daubentoni, besides the usual sterno-trache- 

 ales, which arise in the ordinary way from the costal processes, 

 there are a pair of cleido-tracheales, springing from the 



1 For the tail muscles of the peacock see HEMMING. Proc. Linn. Soc. 1844, 

 p. 212. 



2 GAEROD has figured (in MS.) an ''abnormal Gallus domesticus with a 

 peculiar additional muscle springing by tendinous slips from femur, femoro- 

 caudal, accessory ditto, and semi ten dinosus, and running to gastrocnemius. 1 

 It was the same on both sides. 



