THE ANTHOZOA 



larian ancestor resembling C. viridis. The structure of Tubipora and 

 Favosites is shown in Figs. IX., X., and XI. 



ORDER 2. Alcyonacea, Verrill (pro parte). 



Characters The colony consists of bunches of elongate, cylindrical 

 zooids which, in their proximal portions, are connected together by 

 numerous anastomosing solenia, and are compacted into a fleshy mass, 

 the coenenchyma, by fusion of their own walls and those of the solenia. 



Fio. XII. 



1. A small colony of Alcyonium palmatum, Pallas, with expanded zooids. (Original.) 



2. Vertical section through a small colony of Alcyonium digitatum, Linn., showing th 

 elongated zooid cavities. (Original.) 



3. A colony of Sarcophytum pwlmo, Esper, showing the pileus, P, bearing zooids, and the 

 barren stem, st. One-half natural size. (Original.) 



4. Diagrammatic vertical section through a portion of a colony of Sarcophytum pul 

 showing the retracted autozooids, an, and the siphonozooids, sz, connected by a networl 

 solenia. (After Moseley). 



the 



imo, 

 k of 



The coenenchyma thus forms a stem, sometimes branched, from the 

 surface of which the free portions of the zooids project. 



FAMILY 1. XENIIDAE, Gray (pro parte). The zooids are not retractile. 

 Spicules in the form of minute, feebly calcareous discs, often confined to 

 the ectoderm. The colony consists of a stout, fleshy, sterile stem, some- 

 times bearing short lobose branches, on the expanded upper surface of 

 which the free moieties of the zooids are borne. Genera Xenia, Savigny. 

 Colony monomorphic. Heteroxenia, Kolliker. Colony dimorphic, bearing 

 autozooids and siphonozooids. FAMILY 2. ALCYONIDAE, Verrill. The 

 colony a fleshy stock, sometimes simple and lobose, sometimes irregularly 



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