XIII 



PHYLUM CHORDATA 



369 



into which it discharges its secretion by three ducts (pn. d. 1-3}. 

 A thick-walled glandular pouch, the bursa Fdbricii (b. fair.), lies 

 against the dorsal wall of the cloaca in young Birds and opens 

 into the proctodreum : it atrophies in the adult. 



di.coe crb.k 



pn.d.3 



pn. 



FIG. 081. Columba liyia. Dissection from the right side. The body-wall, with the vertebral 

 column, sternum, brain, &c., are in sagittal section ; portions of the gullet and crop are cut 

 away and the cloaca is opened ; nearly the whole of the ileuni is removed, and the duodenum 

 is displaced outwards, a. ao. aortic arch ; Id. 1, M. 2, bile-ducts ; b. fabr. bursa Fabricii ; 

 rid. cerebellum; co;. right ccecurn ; cpdm. coprodteum ; cr. cere; crb. h. left cerebral hemi- 

 sphere; crp. crop; cr. v. 1, first cervical vertebras ; di.cce. diaccele ; dnt. dentary ; duo. 

 duodenum ; eus. up. aperture of Eustachiau tubes ; giz. gizzard (dotted behind the liver) ; 

 gl. glottis ; guL gullet ; Urn. ileum ; i. orb. .?/>. inter-orbital septum ; M. right kidney ; 

 "ing. right lung ; Ir. liver (right lobe); na. bristle passed from nostril into mouth; obi. stp. 

 oblique septum ; o. gl. oil-gland ; pal. pericardium ; pmx. pre-maxilla ; pn. pancreas ; pn. b. 

 pineal body ; pn<l. 1 3, pancreatic ducts ; pr. cc. right pre-caval ; prdm. proctodasuni ; prvn. 

 proventriculus (dotted behind liver) ; pt. cr. post-caval ; pit/, b. pituitary body ; pyg.st. 

 pygostyle ; /. an. right auricle; r. br. right bronchus; ret. rectum; r. vnt. right ventricle; 

 sp. cd. spinal cord ; spl. spleen (dotted behind liver) ; s. rhb. sinus rhomboidalis ; s. scr. syn- 

 sacrum ; si. carina sterni ; st/r. syrinx; th. c. 1, first, and th. r. 5, fifth thoracic vertebra ; 

 tng. tongue ; tr. trachea; ts. right testis ; u> i . aperture of left ureter; v.rdm. urodteum ; x. df. 

 aperture of left vas deferens. 



Ductless Glands.- -The spleen (spl.) is an ovoid red body, of 

 unusually small proportional size, attached by peritoneum to the 

 right side of the proventriculus. There are paired thyroids at the 

 base of the neck and, in young Pigeons, there is an elongated 



VOL. II. B B 



