Common Pigeon. 177 



e. I. Terminal segment of small intestine ending in the large 

 intestine at/, which, together with it, has been turned over 

 out of the abdominal cavity, on to the animal's left. Two 

 long coils of small intestine have been removed between its 

 terminal segment and the distal end of the duodenum ; the 

 first coil being a fold of great length spirally arranged, and 

 the second a much shorter one arranged like the duodenal 

 fold, which however it exceeds in length. 



/. Large intestine, two small coeca marking its commencement. 

 In the small size of the two coeca the Columbidae contrast 

 with the great mass of the Gallinaceae, 



g. Terminal dilatation of the large intestine which receives the 

 vas deferens and ureter posteriorly and superiorly 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 Cartilaginous 

 Fishes, as also many Lizards. 



h. Testis. 



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

 sinuosities of the pelvic bones. Between the lower and 

 middle lobes the large ischiatic artery and some nerves pass 

 out to the lower hmb. The artery gives a supply of blood 

 to the gland. Between the middle and uj^per lobe of the 

 kidney the small femoral artery passes outwards, and a 

 large vein passes inwards. This vein, besides acting as a 

 ' renal-portar vein and sujiplying the glandular structure 

 of the kidney, communicates directly also with the renal 

 efferent vein. This latter branch is not possessed by cold- 

 blooded Ovipara \, 



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



k. Ureter. 



I. 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 anasto- 



» See Jourdain, Sur la Voine Porte E^nale, Ann. Sci. N:it. Ser. iv., torn. 12, 1860, 

 pp. 156 and 359, and plate 4, fig. 2. 



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