INVERTEBRATE ANIMALS. 1? 



Group 49.— Genus RETEPOEA (Lamarck) ; rHe, a net ; 

 and allies. Polyzoarium chiefly calcareous and rigid. 

 ^ Examples of TuhuUpora, CelU'pora, Idmonea, 

 Hornera, &c., including some very beautiful 

 Retepores and other Polyzoa from the Atlantic 

 Cable. Oldhamia from the Cambrian rocks, 

 possibly a plant. 



Group 50. — Genus FLUSTRA (Linn^us). Saxon Flustrian, 

 to weave ; and allies. Polyzoarium chiefly horny, 

 foliaceous or explanate. 



H Examples of Lepralia, Carbasea, Membranipora, 

 Electra, &c. Observe how closely Amathia 

 spiralis (Lamouroux), from Australia resem- 

 bles in form Archimedipora Archimedea 

 (Lesuer) ; a fossil from the Carboniferous 

 Limestone, Kentucky. A delicate cup-shaped 

 Flustra on Catenicella. 



Group 51.— Genus CATENICELLA (Blainville) ; catena, 

 a chain ; and allies. Polyzoarium chiefly articulated 

 and flexible. 



H Examples of Cellularia, Salicornaria, Bicellaria, 

 Emma, Bugula, dtc. 



Upper Compartment. 

 Diagram of a Polyzoon, and of an " avicularium," 

 or Bird's-head process. Coloured drawings of 

 fresh-water Polyzoa, after Allman. 

 The animals of the Polyzoa are always minute, 

 and live associated in colonies. They are 

 much in advance of the Ccelenterata in com- 

 plexity of structure ; the food canal being 

 entirely shut off from the body-cavity, and the 

 nervous system being well defined. 







