MOLLUSGA OR UNIVALVES. 147 



Family 4. — Semi-Phyllididce* 



The animals of this small family only differ 

 from the last in the situation of the branchiae, 

 which are placed on the right side of the body. 

 The shells are cup-shaped, but nearly flat. 

 There are only two genera. 



19. Pleurobranchus. — Shell thin, nearly 

 flat and obliquely oval; 

 it is internal, or covered 

 by the animal. Animal, 

 head distinct, with two cylindrical tentacular 

 foot large. — There are 7 species recent. 



It is found in the Indian Seas and the Medi- 

 terranean. 



20. Umbrella. — Shell rather irregular, 

 slightly convex on the outside, and with a 

 small, nearly central apex ; margin sharp. 

 Animal, head not very distinct, with four ten- 

 tacula ; foot very large. — There are 2 species 

 recent. 



The Umbrella Indica is met with in the Indian 

 Ocean, and on the coasts of the Isle of France, 



* Les Semi-Phz/Ilidiens 9 Lamarck. 



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