266 DESCRIPTION OF PLATES. 



f. Two long coils of small intestine have been removed between this 

 terminal segment and the distal end of the duodenum. 



f. Large intestine, two coeca marking its commencement. In the small 



size of the coeca the Columbidae contrast with the majority of 

 Gallinaceae. 



g. Terminal dilatation of the large intestine receiving the vas deferens and 



ureter dorsally on each side. In this cloacal arrangement Birds 

 resemble Reptiles and Amphibia ; in all Mammals there is a sinus 

 urogenitalis developed, into which these ducts open. In the absence 

 of a urinary bladder Birds resemble Snakes and many Lizards. 



h. Testis. 



i. Kidney divided into three lobes, which are conformed to the sinuosities 



of the pelvic bones. 

 j. Vas deferens, dilating before its termination in the cloaca. 



k. Ureter. 



/. Teres major muscle, the subscapularis and great part of the scapula 



having been removed. 



m. Right jugular vein receiving the veins from the oesophagus, and by 

 virtue of these vessels, as also of a branch of anastomosis with the 

 left jugular, attaining, as is usual in Birds, a larger size than that 

 vessel. 



n. Right jugular vein in thorax. 



o. Vena cava inferior, entering the auricle to the right of and posteriorly 

 to the entrance of the vena cava superior of the right side. 



/. Lung, showing on its exterior surface indentations corresponding with 

 the ribs. 



q. Right bronchus entering the lung. Between the bronchus and the vena 

 cava inferior we see a portion of the glandular proventriculus, and 

 immediately above the bronchus and below the arch of the aorta, 

 which has been displaced a little upwards, the junction with the jugular 

 of the fragment of vein left to represent the subclavian trunk. 



r> Right innominate artery, which is seen to break up into three main 

 divisions, the- common carotid, the axillary and the pectoral arteries. 



y. Portion of inner tuberosity of humerus which overhangs the pneumatic 

 foramen of the bone. 



z. Gizzard. 



s. Great pectoral muscle, the main depressor of the humerus and wing. Its main 

 tendon is seen turned back at x ; two other tendons which it gives, one 

 to the long extensor, the other to the short extensor of the alar membrane, 

 are not shown in this figure. 



t. Second pectoral, the main elevator of the humerus. 



u. Coracobrachialis inferior, a muscle arising from the inferior and outer three- 

 fifths of the distal part of the coracoid, and inserted into the internal and 



