66 



Basic Structure of Vertebrates 



EXT.JUGULAR 



EXT. JUGULAR 



Subclavian 



NTERCOSTAL 



GLANDSv 



THORACIC DUCT. 

 AZYGOS V.— 



POSTCAVAL - 

 r^^VRENAL 



1 COMMUNICA- 

 TIONS 



LYMPH GLANDS\ 



Fig. 66. Diagrams illustrating the chief lymphatic trunks and their relations to 

 the veins in mammals. Ventral views. (A) South American monkeys. (B) Mammals 

 {Lepus) in which postcaval-renal communications are wanting. (C) Mammals in 

 general. (D) Man. (Postcava and kidneys not shown). 



In all mammals lymph enters the veins at the point of junction between the 

 jugular and the subclavian veins. In most mammals there is also communication 

 between the lymph-vessels and the postcaval and renal veins. In man the right 

 thoracic duct degenerates in part and the only communication with veins is at the 

 root of the jugulars. (Courtesy. Neal and Band: "Chordate Anatomy," Phila- 

 delphia, The Blakiston Company.) 



Afferent lymphatic vessels 



Peripheral 



Lymph sinus 



Capsule 



Medullary 

 cord 



Efferent lymphatic vessels 



Fig. 67. Diagram representing two stages in the development of a lymph-gland. 

 The left half of the diagram is an earlier stage than the right half. (Modified from 

 Bremer: "Text-Book of Histology," Philadelphia. The Blakiston Company.) 



