474 



THM BESPIBATOBT APPARATUS. 



externally by an almost amorphous membrane which divides it into " acini," 

 or gland-granules. Separate acini are often observed on the maia canal. 

 Each lobule is made up of its greyish-white, soft parenchyma composed of 

 free nuclei and small cells, and has a minutely-distributed capillary plexust 



Fig. 244. 



Fig. 245. 



POETION OF THTMtrS 

 GLAND OF CALF, 

 UNFOLDED. 



a, Main canal ; 



COURSE AND TEEMINATION OF THE ABSORBENT 



DUCTS OF THE THYMUS GLAND OF A CALF. 

 1, Internal jugular reins ; 2, Superior vena cava; 

 6, 3, Thoracic duct, dividing into two branches, 



Glandular lobules ; that again unite before terminating in the root 



c, Isolated gland of the left jugular vein ; 4, The two thymic 



granules seated on ducts : that on the left side opening into the 



the main canal. thoracic duct, and the right into the root of 



the corresponding jugular vein. 



The lymphatics terminate in two large ducts that commence at the upper 

 extremities of the lobes of the gland, the thymie ducts, and pass down- 

 ward to terminate at the junction of the jugular and axillary veins at each 

 side.) 



DIFFEEENTLAL CHARAOTEBS IS TBE GLANDIFORM BODIES ANNEXED TO THE RESPIBATOEY 

 APPARATUS IN OTHEB THAN SOLIPED ANIMALS. 



The thyroid lody, peculiar to Mammals, is more developed in Ruminants Padiv- 

 derms, and the Carnivora, than in Solipeda. The two lobes are closer together and 

 often joined by the thyroid isthmus. In the Pig this is very marked, and the gland 

 weU merits its name, as it forms a veritable shield in front of the trachea towards thf. 

 lower part of the neck. - ' 



