PLATE XVI 



1. Bulla aperta entire, seen on the back. 



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



disk " 

 c. .. part containing the shell. 



2. 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. 



Bulla aperta, seen underneath. 



b. The plate serving as a foot. 



c. .. part containing the shell 



d. Pi. part of the branchia:. 

 Bulla aperta-, partly dissected. 



a. The stomach. 



b. .. oesophagus. 

 d. .. branchiae. 



c. The anus. 



e. The heart, 

 y. . . liver. 



e. .. intestine. 



It. .. testicle. 



a. The large right tentaculum 



half developed. 



b. . . hole whence the left 



tentaculum issues. 



c. .. hole for the small tenta- 



culum of the same 

 side. 



dd. .. two lobes of the veil or 

 upper lip. 



eee. . . 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. 



k. The hole for respiration seen 

 within the pulmonary ca- 



«ty. .; VM 



l\ .. diaphragm. 



mu. .. heart and auricle in their 



proper place in the open 



pericardium. 

 o. .. commencement of the great 



artery of the spire. 

 p. .. bag of viscous matter. 

 q. .. first part of the intestine, 

 r. .. second part. 

 ss. .. lobes of the liver. 



Copulas, Mont. (Patella Hungarica, Lin.) detached from its shell and 

 seen on one side. ' 



common orifice of the male 

 organ and oviductus. 



5. The tongue of the Bulla aperta greatly magnified. 



G. 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. 



d. The trunk. 

 ee. .. tentacula. 



f. .. liver and a part of the viscera, 

 which occupy the bottom 

 of the shell. 



a. The foot. 



/>. A sort of ruff which this foot 



has in front, 

 r. The muscle which attaches 



the foot to the shell. 

 Onchidium, under view. 



Parmacella, seen on the back : the shell has been taken away, and only 

 its impression remains. 



The horned Planorbis, with its shell. 



The animal of the Cyprosa. 



Conus. 



Emargmula entire. 



Nervous system of the Fissurella. 



Animal of the Crepidula, detached from its shell, seen above ; the ab- 

 domen and branchial cavity in their natural position. 



Shell of the Crepidula seen underneath. 



a. Plate which retains the point of the abdomen. 



Animal of the Crepidula, detached from its shell, and the upper parti- 

 tion of its branchial cavity turned back to shew the branchice. 



IS. Testacellus halyotideiiSy animal and shell. 



