r ,8 ATLAS OF BIOLOGY. 



The excretory groove, gr., cut across, lies in life altogether to the left of the respirator 



orifice. 



The rerjo-pericardial communication is not figured ; it is very small, and differs in no 

 important respect from that drawn and described by Niisslin (76) for Helix pomatia. 



FIG. XIV. Obliquely transverse section through the whole body and shell, taken just 

 in front of the columella. Spirit preparation, x 3. 



FIG. XV. Dissection from the right side, after injection from the large pulmonary 

 vein, p.v.', to show the chief arteries. 



The visceral sac and body- wall of the right side were dissected away in toto ; the 

 retractor muscles, genital ducts, and rectum were all in part removed, as shown by their cut 

 ends drawn. The rectum was turned back, and the heart and right lobe of the liver a 

 little displaced. All else is figured in situ. x 2. 



The artery running longitudinally along the foot overlies the pedal gland. 



FIG. XVI. Dissection, after injection, to show the leading venous sinuses, together 

 with the respiratory and renal capillary systems. 



The arteries were injected from the pulmonary vein (afferent pulmonary vessel), p.v.', and 

 the venous lacunae, pulmonary circulus, and afferent pulmonary vessels from the point 

 marked *. 



The pulmonary sac was severed close alongside the rectum, in order to show the whole 

 respiratory plexus in one view, x 2. 



The position of the lateral pedal sinus, l.s., is indicated in life by a light band which 

 runs along the side of the foot. On withdrawal of the body into the shell this sinus becomes 

 greatly distended by displacement of the perivisceral fluid, and I know of no more satisfac- 

 tory means of demonstrating a lacunar blood system, than that afforded by injection from 

 this receptacle. 



