THE BLOOD AXD LYMPH VESSELS OF THE LUNG OF 

 XECTUEUS MACULATUS. 



BY 



WILLIAM SNOW MILLER. 



Associate Professor of Anatomy, University of Wisconsin. 



With 3 Text Figures and 2 Plates. 



Anatomical Relations of the Lungs. — The lungs of Necturus 

 maculatus consist of two elongated cylindrical sacs which are situated 

 one on each side of the body cavity. Anteriorly they meet in the mid- 

 line and communicate by means of a narrow slit, the glottis, with the 

 short, wide pharynx. No septa are present in the lungs and both inner 

 and outer surfaces are smooth except for such irregularities as are 

 occasioned by the blood vessels. 



When fully distended the lungs measure, in an adult animal, from 

 80 to 100 mm. in length and from 7.5 to 10 mm. in diameter; they are 

 slightly crescentic in shape (Fig. 1) and enclose an elongated oval 

 space which is occupied by the posterior portion of the oesophagus, the 

 spindle-shaped stomach and the anterior portion of the intestine. 



Each lung is attached throughout nearly its entire length to a fold of 

 the peritoneum; the right lung to one which extends from the liver to 

 the mid-dorsal body wall, the left, to one which extends from the 

 stomach to the mid-dorsal body wall. In an average sized animal only 

 15 or 25 mm. of the normally distended lung is free from this peritoneal 

 attachment. 



The Blood Vessels. — Three afferent branchial arteries convey the 

 blood on each side from the heart to the gills. Each artery runs along 

 the ventral border of tlie corresponding gill giving rise to numerous fine 

 branches which break up into a capillary network. From this capillarv 

 network numerous radicles unite to form on the dorsal border of each 

 o-ill an efferent branchial artery. There are thus formed on eacli side 

 three efferent branchial arteries (Fig. 1, E. B.) which form by their union 

 the right and left aortic roots (Fig. 1, R. A. and R. A.') these, in turn, 

 unite in the mid-line dorsal to the anterior end of the stomach to form 

 the aorta (Fig. 1. .4.). 



Ameiiican Journal of .\NATo.My. — Vol. IV. 



