44:8 The Vessels of the lAing of Necturiis Mnciilalus 



Along the course of the main artery three lymph trunks are usually 

 found placed nearly equidistant from one another and connected together 

 by numerous anastomosing branches (PI. II). The main lymph trunks 

 show great irregularity in size; sometimes, by their wide dilatations 

 coming nearly into contact, the artery is practically hidden from view 

 (PI. I, Fig. 1). As the artery approaches the tip of the lung the num- 

 ber of lymph trunks are, in most lungs, reduced to two, placed one on 

 either side of the artery. Numerous anastomosing branches connect 

 the two lymph vessels. 



Each lateral branch of the pulmonary artery as it leaves the main 

 trunk is accompanied by two lymph vessels which arise from the main 

 trunks, and like the main trunks they are connected together by fine 

 anastomosing branches (PL II). The lymph vessels accompanying the 

 branches of the pulmonary artery can be traced across the interval be- 

 tween the pulmonary artery and pulmonary vein to their union with 

 one of the main lymph trunks about the pulmonary vein (PL II). 

 When a branch of the pulmonary artery forms a direct anastomosis with 

 the pulmonary veins there can usually be recognized two accompanying 

 lymph vessels which join directly one of the main lymph trunks about 

 ihe pulmonary vein. 



At the root of the lung the network of lymph vessels about the pul- 

 monary artery usually forms two large trunks which join the exceedingly 

 rich network of lymph vessels in the wall of the stomach on its dorsal 

 side (PL I, Fig. 1). In some animals small lymph vessels pass from 

 the peri-arterial network about the left pulmonary artery along the 

 dorsal mesogastrium to join this same network. 



In some lungs one of the two main trunks above mentioned passes 

 around to the ventral side of the lung and forms an anastomosis with 

 the lymph vessels about the pulmonary vein (PL I, Fig. 1). 



Hoffmann says in regard to the lymph vessels of the lung of Rana : 

 ■*' Die Lymphgefasse begleiten in der Lunge ausschliesslich die arteriel- 

 len, nie die venosen Blutgefasse." Suchard, in his description of the 

 lymph vessels of the lung of Triton, says : " les branches du reseau peri- 

 arteriel sont moins nombreuses et moins volumineuses que celles du 

 Teseau peri-veineux." We shall see that neither of these statements 

 holds true for the lung of Necturus. 



The main trunk of the pulmonary vein is accompanied by two large 

 lymph trunks which are connected together by less numerous anastomosing 

 branches than is the case with the lymph trunks about the artery (PL II). 

 In some lungs they are apparently absent or for some reason they faiJ 



