PLATE X. 

 Paludicella Ehrenbergi. 



Fig. 



1. Paludicella Ehrenbergi, attached to a submerged stone. Natural size. 



2. A portion of the same magnified. 



3. A very much enlarged drawing of a cell with the polypide retracted ; showing tlie 



anatomical details. 



4. A cell seen in section with the polypide exserted, and exhibiting anatomical details. The 



ovary and testis are here fully developed, while in fig. 3 they are represented in an 

 undeveloped state. 



5. Lophophore viewed upon the upper surface, with the mouth, and roots of the tentacula. 



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