THE ANTHOZOA 



The Anthozoan zooid is further characterised by the following 

 anatomical features : The coelenteron is not a simple cavity, as 

 in the Hydroid zooid, but is divided by a number of radial folds 

 of tissue into a corresponding number of radial chambers. These 

 radial folds of tissue are called mesenteries, or by German authors, 



FIG. II. 



1. Section through the stoinodaeum of Adamsia rondcletii. Diagrammatic, ec, ectoderm 

 showing elongate ciliated epithelial cells, two kinds of gland cells, and nematocysts. Beneath 

 the ectoderm is a layer of nerve fibrils, mg, mesogloea, containing fibrils and a few stellate 

 cells ; en, endoderm composed of columnar ciliated cells and containing two kinds of gland 

 cells. 



2. Ectoderm cells from the body wall of Corynactis viridis, partly isolated. 



3. A portion of epithelium from the tentacle of Ammonia sulcata, consisting of three 

 supporting cells and one sense cell. 



4. A cnidoblast with enclosed nematocyst from the tentacle of Anemonia sulcata. 



5. Two ganglion cells from the ectoderm of the peristome of Anemonia svlcata. 



6. An epithelio-muscular cell from the extended tentacle of Adamsia ronMetii. 6a. The 

 same from a contracted tentacle. 66 and 6c Endoderm cells with symbiotic zooxanthellae from 

 the tentacle of Anemonia sulcata. 



7, 7a. Two gland cells from the stomodaeum of Anemonia sukata. 76. A flagellate cell 

 from the same species. 



8. A gland cell from the stomodaeum of Anemonia svlcata. (2 original ; all the others 

 after O. and R. Hertwig.) 



sarcosepta or simply septa. There is no objection to the use of 

 the term sarcoseptum, but the term septum must be avoided, 

 because it denotes a distinct set of structures in one of the groups 

 of the Anthozoa. In this chapter the term mesentery will always 



