MARINE POLYZOA. 97 



Fam. 14. SELEXARIAD^. 



Polyzoary more or less regularly orbicular, convex on one side, 

 plane or concave on the other, probably free. Furnished with 

 large and powerful vibracula (probably locomotive) (often having 

 arenaceous particles affixed in the centre of the under surface). 



SYNOPSIS OF GENERA. 



1. Each cell with a ribraculum at its apex. 



1. CUPULARIA. 



2. The cells and ribracula in alternate rows radiating from the 

 centre. 



LUNULITES. 



3. Certain of the cells only, furnished with vibracula. 

 3. SELENARIA. 



1. CUPULARIA. 



Each cell throughout the polyzoarium with a vibracular ceil at 



its apex. 



Cupularia, Lamouroujc, Exposit. p. 44 (proposed). 



Lunulites, id. ib. ipart.) ; Defrance, Diet, des Sc. Nat. (part.) ; 

 Deslongch. Encyclop. Zooph. B. (part.); Goldfuss, Petrefact. 

 Germ, (part.); Blainrille, Man. d'Actin. (part.); Gray, Spi- 

 cilegia Zoologica, pt. 1. p. 8; Cuvier et Brongniart, De- 

 it, geolog. des Environs de Paris (part.) ; Lonsdale. Mio- 

 cene Fossils from A\ America, Journal of Geol. Society, i. 

 503 (not Eocene Fossils, ib. p. 531) ; Michelin, Icon. Zoo- 

 phyt. (part.). 



Fenestella, Lonsdale (Append. Geol. of Russia) (part.). 



Besides the peculiar formation of the polyzoary, all the Sele- 

 nariada are distinguished by the circumstance that the cells of 

 which it is constituted are of two kinds, usually differing in size, 

 the one being smaller than the other. The distinction between 

 the different genera into which I have thought it convenient to 

 divide the family is derived solely from the different relative 

 position of these two kinds of cells to each other, or to the entire 

 polyzoarium. The propriety of the division of the Lunulite 

 sroup into two genera appears to have occurred to Lamouroux, 



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