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bj an inflection of the muscular layer of the Integument 

 of the body. The renal organ is placed to the right of 

 the heart, and at its posterior part is perforated by the 

 aorta. 



Vaginulus. The pulmonary cavity is situated be- 

 tween the muscular peritoneum and the integument of 

 the body. Its principal portion is placed upon the right 

 side, anterior to the middle, but extends to the left side, 

 over the back, and along the right side to the pulmonary 

 aperture, between the tail and posterior extremity of the 

 podal disc. The heart is placed in the anterior portion 

 of the cavity. The auricle receives a vem from the right 

 and another from the left side. The renal organ is 

 placed posterior to the heart, between the passage lead- 

 ing from the pulmonary cavity to its orifice, and the 

 course of the rectum. 



Helix. In this genus, as is also the case in all the 

 testaceous genera under examination, the pulmonary 

 chamber is comparatively very large, for reasons already 

 stated, and occupies a position on the outside of the 

 lower one or two whorls of the turbinated mass of the 

 viscera. In front, it is bounded by the collar, in the 

 right side of which is the pulmonary orifice. The floor 

 of the cavity is formed, as in slugs generally, by the 

 muscular peritoneum. The roof, or outer wall, is occu- 

 pied on the right side by the rectum, posteriorly by the 

 heart and renal organ, and anteriorly by the pulmonary 



