srn-ci,Ass in TABULATA OOTOCORALLA 105 



titenopora, Lonsd. 1 branching or lobate coralla composed of fine tubular 

 coi-allitcs radiating outwards and becoming reflexed. Walls thickened by 

 annular deposits of stereoplasma ; tabulae scanty. Abundant in Carboniferous 

 and /echstein. 



Geinitzella, Waag. and Wentz. Like the preceding, but with walls only* 

 slightly thickened. Carboniferous to Zechstein. 



? Neuropora, Bronn. (Chri/saora, Lamx.), (Fig. 189). Ramose or tuberous 

 coralla, composed of long, polygonal tubes, nearly uniform in size, and with 

 mouths separated into groups by elevated, non - tubular ridges ; tabulae 

 numerous. Jurassic and Cretaceous. 



Family 6. Fistuliporidae. Waagen and Wentzel. ^/? '!?'** 



Encrusting, massive, or branching coralla, composed of two series of fine tubiform 

 corallites. Walls compact ; tabulae Iwrizontcil ; septa wanting. Autopores multiply- 

 ing by coenenchymal gemmation, mesopores by fission. Silurian to Zechstein. 



The Fistuliporidae resemble the Helioporidae in a number of particulars, 

 especially as regards the coenenchymal gemmation of the autopores. Waagen 

 assigns them to the vicinity of the Helioporidae, while Nicholson regards them 

 as a sub-family of the Monticuliporidae. 



Fistulipora, M'Coy. Corallum composed of two series of tubiform corallites ; 

 autopores round or sub-triangular in contour, and embedded in a coenenchyma 

 constituted of the smaller mesopores. The latter are much more closely 

 tabulate than the autopores, and give the coenenchyma a vesicular, multicellular 

 appearance. Walls of the autopores are thickened on one side, and- frequently 

 provided with two septa-like processes. Common in Devonian, Carboniferous, 

 and Permian. 



Callopora, Hall ; Prasopora, Nich. Ordovician and Silurian. Labechia, E. 

 and H., occurring in the Ordovician and Silurian, probably also belongs here. 



Geological Range of the Tabulata. 



With but few exceptions, the Tabulata are restricted to the Palaeozoic 

 formations, and from the Ordovician to the Carboniferous periods inclusive are 

 prominently concerned along with the Tetracoralla and Hydrozoa (Stromotoporidae) 

 in the building of coral reefs. Of the six families composing the Tabulata, the 

 Halysitidae alone are confined to the Silurian ; the rest are all more or less 

 plentiful from the Ordovician to the Carboniferous; while the Fistulip<>r'nli- 

 persist as late as the Zechstein, and the Chaetetidae range from the Ordovician 

 to the Cretaceous. 



Sub-Class 3. OCTOCORALLA. Haeckel. 



(Octadinia, Ehrenberg; Alcyonaria, Milne-Edwards.) 



Composite colonies, rarely simple polyps, the individuals provided with eight 

 mesenterial folds and eight broad, pinnately fringed, or plumose tentacles, which form 

 a single cycle about the mouth. 



Hard skeletal elements are very generally developed in the Octocoi'alla, being 

 absent in comparatively few forms, and are remarkable for their manifold 



