EXPLANATION OF PLATE L 



BRIAREUM ASBESTINUM.i PALL. 



Fig. I. Youii a- zoanthodeme, reduced one-half. 



Fig. 2. Expanded polyp greatly enlarged: a, surface of zoanthodeme: b. b, 



b, mesenteries showing through from interior; c, c, expanded tentacles; 

 d, d, d, tentacular papill3e. 



Fig. 3. Tentacle taken fresh from li-oing polyp and pressed under a cover 

 glass: a, a, a, tentacular papillae; b, b, globular mesodermal cells. 



Fig. 4. Tentacular papilla from fresh tentacle: a, a, ciliated ectodermal 

 cells; b, b, globular mesodermal cells; c, c, cilia. 



Fici. 5. Single globular mesodermal cell: a, cell wall ; b, granular pigment; 



c, nucleus. 



Fig 6. Se<rment of a transverse section of branch of zoanthodeme: a, a, a, 

 ectoderm, covering zoanthodeme and pol^'ps; b, b, endoderm lining 

 calicles; c, c, retractor muscles of polvps; d, d, corvoluted mesenterial 

 filaments; e, e, ova attached to mesenterial muscles; f, gullet of polvp; 

 g, g, expanded tentacles of polyp; h, h, tentacular papillse; i, i, i, 

 water-vascular canals in cross section; j, j, j, spicules embedded in 

 coenenchyma. 



Fig. 7. Cross-section of folyp near base of tentacles: a, endodermal lining of 

 calicle; b, ectodermal investtnent of tentacle; c, endodermal lining of 

 tentacle; d, d, mesenteries; e, e, retractor muscles attached to mesen- 

 teries; f, f, spaces (intermesenterial); g, endodermal lining of gullet. 



Fig. S. Transverse section of tentacle: a, ectodermal cells; b, line indicating 

 muscle layer; c, globular mesodermal cells; d, columnar endodermal 

 cells lining tentacle and surrounding tentacular cavity. 



Fig. 9. Stellate '■'■connective tissue" cells of coenenchyma : a, anastomosing pro- 

 cesses; b, granular protoplasm; c, nucleus. 



Fig. 10. Other cells supposed to contain forming spicules. 



Fig. II. Lining of -water-vascular canal showing endothelial cells. 



Figs. 12-23. Characteristic spicules.^ 



Fig. 24. Transverse section of spicule softened by acid, highly magnified: a, 

 pellicle; b, calcareous salts; c, line of separation between apposed 

 halves. 



1 This name is incorrectly spelled " Asbestrium " on the plate. 



2 All spicules on these Plates are drawn to the same scale except those on 

 Plate X. 



