48 DESCRIPTIONS OF PREPARATIONS. 



Plate ii, infra), the pectoralis tertius audorum, s. coracobrachialis inferior, No. 1 6, 

 Schoepss ; and the coracobrachialis superior. The ' coracobrachial muscular ap- 

 paratus ' has been shown by Professor Wood, Journal of Anatomy and Physiology, 

 i. 1866, p. 55, to be somewhat similarly multifid in many mammals normally and in 

 man occasionally. 



The crop forms a sac with bilateral glandular 1 pouches at the lower end 

 of the distended oesophagus. As in the oesophagus of all Sauropsida, the 

 muscular coat may be seen to consist of two layers, the outer one of which 

 lies transversely 2 , and the inner one parallel to the long axis of the digestive 

 tube, whilst both alike consist of unstriped fibres, and thus contrast in two 

 points with the muscular coat of both Mammals and Fishes. It rests on 

 either side upon the furcula and the muscles arising from it. In the cavity 

 of the thorax a black bristle has been passed between the proventriculus 

 and the aorta as this vessel arches over from the left to the right. The 

 right side of the heart rests upon the right lobe of the liver from which 

 the vena cava inferior is seen to pass up into the right auricle, entering 

 it at a point a little superiorly as well as posteriorly placed to that at which 

 the vena cava superior of the right side opens into it. The left lobe of 

 the liver is, like the right, deeply excavated on its inner aspect for the 

 reception of the heart ; and it is still more extensively excavated on its 

 under surface for the reception of the powerful gizzard, so as to be less 

 than one-half the size of the other main lobe of the gland. The veins from 

 the upper extremity and shoulder are cut short at their point of junction 

 with the jugular to form the vena cava superior. The pneumogastric 

 nerve is seen in relation superiorly with the jugular vein ; superiorly again, 

 and internally to the nerve, we see the proventriculus ; and superiorly 

 again to it, the longi colli muscles arising from the vertebral hypapophyses. 

 Tracing the aorta backwards towards the heart from the point where it 

 arched over the right bronchus, which, together with the pulmonary artery 

 placed before it and the pulmonary vein placed behind it, has been removed 

 in this dissection, we see it pass behind the vena cava superior dextra, and 

 give off the two arteriae innominatae, one for either side of the body, very 

 close to the base of the heart. These two arteries together with the 

 pulmonary artery give a characteristic appearance to the region at the 

 base of the heart in all Birds. Each arteria innominata divides into a 

 common carotid 3 and a subclavian trunk. The subclavian, after giving 

 off a small branch homologous with the internal mammary artery of 



1 This is the usually accepted statement: but see p. 53, infra. 



2 Gulliver, P. Z. S. 1842, 1869, 1870; Leydig, Fische und Reptilien, 1853, p. 41 ; Histologie, 

 1857, p. 324- 



3 There are two carotids in all Columbae and in the majority of non-passerine birds, but in no 

 true Passerines. 



