CLASSIFICATIONS OF ZOOPHYTES. 455 



b b. Cells in pairs, attached by the back, the orifices with 

 opposite aspects. 

 Notamia. 

 a a. Cells single. 



Eucratia. 

 Anguinaria. 

 A A. SJieath membranaceous, cells enlarged externally and lateral. 



SERTULARIADiE. 



I. Base of the cells broad, coalescing with the stem. 



a. Cells on opposite sides of the stem. 

 Sertularia, 

 Dynameua. 

 Thuiaria. 

 a a. Cells unilateral. 



Antennularia. 



Plumularia. 



Serialaria. 



II. Base of the cells narrow, or pedunculated. 



Campanularia. 

 Valkeria. 

 Cymodocia. 

 AAA. Sheath meynhranaceous ; the cells are the simple extremities of 

 the branches. — TuBULARiADiE, 

 Tubularia. 

 Plumatella. 



IV. NUDA. 



Polypi naked, the mouth with marginal tentacula. 



Coryna. 

 Hydra. 



Latreille's method may next be noticed. He, following La- 

 marck, divides the animal kingdom into three primary sections, 

 the last of which is denominated Acephala, which, with various 

 other classes, includes all the Zoophyta. The Actinia and Lu- 

 cernaria constitute a distinct class — HeliantJioida — which is 

 placed between the sea-stars (Echinodermata), and sea-jellies, 

 (Acalepha), being superior to the latter and to zoophytes by 

 their organization, in which Spix had detected a nervous system. 

 The Polypes follow the sea-jellies, and are subdivided thus : 



