100 



COELENTERATA ANTHOZOA 



SUB-BRANCH IT 



Striatopora, Hall (Fig. 176). Like the preceding, but with tubes contracted 

 by stereoplasma at a greater depth, so as to give the calices a funnel-shaped 

 appearance. Silurian and Devonian. 



Alveolites, Lam. (Fig. 177). Corallum massive or branching, composed of 

 small, contiguous, compressed, thin-walled corallites, with obliquely opening 

 triangular or semilunar calices. Septa very faint, represented merely by ridges 



FIG. 177. 



A, Alveolites suborbicularis, Lara. Middle Devonian ; Gerolstein, Eit'el. 

 Natural size. B and C, Alveolites Labecliel, E. and H. Silurian (Wenlock) ; 



FIG. 178. 



Pleurodictyum problenu i tic urn, 

 Goldf. Lower Devonian; 

 Coblenz. Natural size. Vermi- 



. , , . . . . - 



Ironbridge, England. Tangential and vertical sections, 10/1 (after Nicholson). form foreign body in the centre. 



or rows of spinules, sometimes but a single row present. Mural pores of large 

 size, irregularly distributed. Very common in Silurian and Devonian. 



Cladopora, Hall. Coenites, Eichw. Silurian and Devonian. 



Pleurodictyum, Goldf. (Fig. 178). Corallum depressed, discoidal, circular, 

 or elliptical in contour, lower surface covered with concentrically striated 



FIG. 179. 



Michelinia favosa, do Kon. Carboniferous Limestone ; Toujmay, Belgium. A, Corallum from above. 

 B, Lower surface with radiciform epithecal processes. C, Vertical section (after Gaudry). 



epitheca, and frequently with foreign vermiform body occupying centre of the 

 base. Corallites small, polygonal, contracted inf eriorly so as to become funnel- 

 shaped. Septa represented by faint marginal ridges, or obsolete. Walls 

 pierced by irregularly distributed mural pores. Tabulae scanty. Devonian. 

 P. p'ollematicum, Goldfuss, is tolerably abundant in the Lower Devonian 

 " Spirifera sandstone " of the Eifel, but is only known in the form of casts. 



