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 



FIG. 170. Pulmonary veins, heart, and arterial system of Helix (after Howes). The 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 ; 6, hermaphrodite gland ; 

 7, columellar muscle ; S, aorta visceralis ; !>, salivary glands ; 10, aorta cephalica. 



under 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 



Fio. 171. Vascular system of Limax, aft or drawings combined by Leuckart from Delle Chiaje 

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

 -4, auricle ; (', ventricle ; VR, 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 ; A', 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 



