204 



COMPARATIVE ANATOMY 



CHAP. 



runs along the thickened edge of the mantle which concresces with the nuchal integu- 

 ment. From this vein spring numerous venous vessels which spread out on the 



.•#»!**..^V- 



FiG. 170. — Pulmonary veins, heart, and arterial system of Helix (after Howes). Tlie mantle 

 (roof of pulmonary cavity) is cut open and turned back. 1, Pulmonary vein (efferent pulmonary 

 vessel); 2, kidney; 3, auricle; 4, ventricle; 5, rectum, cut through; 0, hermaphrodite gland; 

 7, columellar muscle ; S, aorta vi^ceralis ; P, salivary glands ; 10, aorta cephalica. 



nnder surface of the mantle, i.e. on the roof of the mantle cavity, and there form a 

 delicate respiratory network. In this network the blood becomes arterial, and is 



^Z Ax 



Fiu. 171. —Vascular system of Limax, after drawings combined by Leuckart fiom Delle CMaje 

 and Simroth. The veins carrying tlip venous blood out of the body into the lungs are black. 

 A, auricle ; V, ventricle ; Vli, venous circular sinus of the pulmonary cavity ; Ax, aorta cephalica ; 

 Ay, aorta visceralis ; M, muscular stomach ; ZD, hermaphrodite gland ; //, digestive gland ; /, in ■ 



testine ; AL, respiratory aperture ; ,Y, arteria genitalis. 



next conducted through many vessels into the large pulmonary vein (vena pulmon- 

 aris), which runs back almost parallel to the rectum along the roof of the mantle 



