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7. EoLIDlA. 



Branchiae like plates or 

 leaves, in transversal rows 

 on the two sides of the 

 back. PL 15, fig. 6. 



8. Tercipes. Cuv. 



A row of branchiae (1) 2 Tentacula. Walk on their back, 



along each side of the 

 back. 



ORDER II. INFEROBRANCHI. 



GENERA. 



I. Phyllidia. (2) Cuv. 



Mantle naked, general- 1 Tentaculum on each. Mouth a small trunk, 

 ly coriaceous. PL 15, fig. side of the mouth, and 

 10, 11, 12. 2 from above the two 



small cavities of the 



mantle. 



2. Diphyllidia. 



Mantle more pointed 1 Pointed tentaculum 

 behind : head semicircu- and a slight tubercle on 

 lar. each side of the head. 



(1) These are each terminated by a little sucker,and serve as feet for walking on 

 the back. 



(2) Their heart is towards the middle of the back, the stomach is simple and 

 membranous, and the intestine short. 



