PLATE XVI 



Bulla aperta entire, seen on the back. 



a. The fleshy plate which covers the front of the body, or the tentacular 

 disk 



c. .. part containing the shell. 



Bulla aperta on the right side, with the ventral fleshy plate separated 

 from the dorsal, to shew what is between them. 



a. The tentacular disk. 



b. .. plate serving as a foot. 



m 



3. Bulla aperta, seen underneath. 



b. The plate serving as a foot. 



c. .. part containing the shell. 



d. A part of the branchiae. 



4. Bulla aperta, partly dissected. 



a. The stomach. 



b. .. oesophagus. 

 d. .. branchiae. 



e. The anus. 



f. .. common orifice of the male 

 organ and oviductus. 



e. The heart. 



f. . . liver. 



g. .. intestine. 



h. .. testicle. 



a. 



The large 



5. The tongue of the Bulla aperta greatly magnified. 



6. Helix pomatia, taken from its shell, and seen on the left side : a large 



portion of the covering of the pulmonary cavity has been taken away 

 to shew its position ; also the teguments of the remainder of the spire, 

 to shew the situation of the heart, the bag of viscous matter, etc. 



The hole for respiration seen 

 within the pulmonary ca- 

 vity. 



diaphragm. 



heart and auricle in their 

 proper place in the open 

 pericardium. 



commencement of the great 

 artery of the spire. 



dd. 



right tentaculum 

 half developed, 

 hole whence the left 



tentaculum issues, 

 hole for the small tenta- 

 culum of the same 

 side. 



two lobes of the veil or 



upper lip. 

 edges of the foot. 

 jf. Two of the lobes placed un- 

 der the collar. 

 gg. The pad of the collar. 

 hh. .. place where the cover- 

 ing of the pulmonary 

 cavity has been cut 

 away. 

 i. .. rectum. 



eee. 



mn, 



7- 

 r. 



ss. 



bas; of viscous matter, 

 first part of the intestine, 

 second part, 

 lobes of the liver. 



