POLYGYRA ALBOLABRIS AND LIMAX MAXIMUS 283 



body, not being on the surface as is frequently the case with the 

 arteries. As in P. a 1 b o 1 a b r i s, they are not simply lacunae or 

 spaces in the body, but have a di&tinct wall. 



The branches of the arteries grow smaller and smaller, and 

 finally consist of an anastomosing network, which communicates 

 with a similar network of veins; these capillaries gradually coal- 

 escing, forming larger branches, which combine to form large 

 veins, connecting with the sinus of the pulmonary cavity. There 

 are two veins parallel with, and in close contiguity to the pedal 

 gland or sinus. 



The two largest veins are situated in the integument of the sides 

 of the body, one on each side. They are connected with the ar- 

 teries by innumerable ramifications. They are illustrated on plate 



18, figures 2 and 3; but only the large vessels are shown, the smaller 

 ones not being represented. There are also smaller veins in the 

 lateral anterior parts of the integument, and a large vein in the 

 dorsal part of the integument. 



The blood proceeds from the heart through the arteries, entering 

 the veins from the arteries, and carried by them to the renal organ 

 and the pulmonary cavity, where it is aerated, and returned by the 

 large pulmonary veins to the auricle, thence to the ventricle. 



Kidney. The kidney is situated in contiguity to the heart (pi. 



19, fig. 3), and is a large subovate, glandular organ. From the 

 lower right side proceeds a duct, which continues along the lower 

 part of the pulmonary cavity to the rectum, continuing along- 

 side of this; curving near the extremity, the parts of the curve 

 being in apposition to the rectum, and opening in close contiguity 

 to the anus. 



Nervous system 



Plate 22 



The two principal ganglionic masses are the supra and infra- 

 esophageal (i, 2). 



The supra-esophageal ganglia are situated above the esopha- 

 gus, and just posterior to the buccal body, when the animal is 

 extended. Of course when the animal is contracted the relative 

 positions are altered. The ganglionic mass consists of three pairs 



