346 Leidy's Anatomy of the Animal 
be intermediate to the lung of the pulmonated gasteropods 
and the distinct branchia of the order to which the animal 
under description properly belongs. From the branchia, on 
the left side, courses the branchial vein (14) to the heart, situ- 
ated at the posterior part of the cavity. "The heart (15) is 
systemic, composed of an auricle and ventricle, and is enclosed 
within a pericardium. From it pass off two aortic branches ; 
one of which (16) is seen, in the figure, in its course to the 
head; the other goes to the liver. 
On the right of the heart, and separated from the réspira- 
tory chamber by a membrane, is the renal organ (17) ; its duct 
passes along the outside of the rectum. 
The visceral sac (18) is musculo-membranous, and has its 
origin from the lateral edges of the retractor muscle of the foot 
and the margin of the excavation of the foot. It extends to 
the very point of the turbinated mass of the animal, and 
encloses the greater part of the digestive and generative appa- 
ratus. 
The mouth opens into the cavity of a muscular organ, the i 
buccal mass (19); this contains a cartilaginous body, consid- 
ered as the tongue, upon the surface of which is placed part - 
of a lamina having a very complex arrangement of hooklets 
 uponit. This lamina is about one and a half inches in length ; 
it protrudes from the buccal mass behind, and forms a coil (20), 
which is terminated by a small glandular body. A portion of 
this lamina, highly magnified, is represented in fig. 2. 
From the upper part of the buccal mass proceeds a short 
cesophagus to the stomach. The stomach (21) passes upwards, 
forms a duodenal pouch (22) for the reception of the hepatic 
duct from the liver, and terminates in the small intestine (23); 
which, after a turn in the liver, joins the rectum, upon 7 
right side of the animal. ‘The rectum (24) courses along the 
right side of the pulmonary cavity, and terminates by a com” 
tracted, unattached and projecting extremity (25), immediate? 
beneath the collar, on the right side of the animal. ee 
The salivary glands (26) are small, situated on each side 
