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general is composed of epidermic tissue, and constitutes a stem 

 or axis in the centre of tlie compound mass formed by the 

 gemmation of the Pol}^i. This sclerobasis is always covered by 

 soft dermic tissue, and increases by the addition of concentric 

 layers. It comprises three famiUes, — Alcyonidce, Gorgonidce, 

 Pennatulidoe. 



3rd Order. — Podactinakia. — The Polypi have the gastric 

 cavity surrounded by four vertical membranaceous septa, at the 

 upper end of which four pairs of intestiniform reproductive 

 organs are situated. The tentacula, discoidal, pedunculated, 

 not tubular, as in Zoanthaeia and Alctonaria The mouth 

 proboscidiform, and the fauces surrounded by numerous internal 

 fihform, contractile appendages. The only known representative 

 of this order is the genus Lucernaria, Miiller, which has no 

 coralligenous form, and is now removed to the class Hydrozoa. 



1st Order.— ZOA^TBAUiA. 



The sclerenchymatous Zoantharia are in fact the group to 

 which the true hving and fossil Corals belong. Six principal 

 divisions may be made of this section, and these are, the 



Zoantharia aporosa Zoantharia rugosa 



tabulata txihulosa 



perforata ■ caulimdata 



The ZoANTHAKiA APOEOSA havc the corallum composed 

 essentially of lamellar dermic sclerenchyma, the septal system is 

 highly developed, and constructed of six primitive elements, the 

 laminae are imperforate, and they are the most stellular of all. 



The ZoANTHAKiA PERFORATA have the coraUum composed of 

 a porous or reticulate sclerenchyma, with a septal system of six 

 elements, represented only by a series of trabiculse; dissepiments 

 rudimentary ; and no tabulse. 



The Zoantharia tabttlata have the corallum composed of a 

 well developed mural system, and the visceral chambers divided 

 into a series of stories by complete transverse diaphragms or 

 tabulse. The septal apparatus is rudimentary. 



