no 



COELENTERATA— ANTHOZOA 



rHTLUM II 



size and fragile constitution. They have been detected as yet only by Pocta ^ 

 in the Upper Cretaceous strata near Laun, Bohemia. 



n Family 2. Pennatulidae Milne Edwards and Hainie. 



Fohjji stocks until base embedded in sand or mud, and icith horny 

 or calcareous sclerobase ; 2^ohjps dimorphic. 



Slender, round or quadrate calcareous axes referable to the 

 Pennatulidae have been detected with certainty only in the 

 Trias [Prographidaria Freeh.), Cretaceous (Pavonaria Cuv. ; 

 Pennatulites and Palaeosceptron Cocchi ; Glyptosceptron Bohm), 

 and Tertiary (Graphularia E. and H.) (Fig. 173). 



Fig. 17B. 



Graphularia de- 

 sertorvm Zitt. 

 Numraulitic lime- 

 stone (Eocene) ; 

 Farafreh, Libyan 

 Desert, Africa, a, 

 Axis, natural size ; 



b, Section of same ; 



c, Sti'iatod .surface, 

 enlarged. 



Family 3. Gorgonidae Milne Edwards and Haime. 



Fixed, branching or fan- shaped colonies, with horny or calcareous 

 solid sclerobase, or tvith jointed axis composed of alternating horny 

 and calcareous segments. 



All the genera possessing horny, flexible axes (Gorgonia, 

 Ehipidogorgia, etc.) are perishable. Detached remains referable 

 to Primnoa, Gorgonclla and Virgularia, the axes of which are 

 composed of both horny and calcareous layers, have been 

 described from the Tertiary. In the genus Isis the axis con- 

 sists of cylindrical calcareous segments alternating with horny 

 connecting joints. It is found fossil in the Tertiary, and has 

 been reported also from the Cretaceous. The genus Moltkia, 

 occurring in the Upper Cretaceous, has cylindrical joints which 

 are pitted with slight depressions indicating the position of 

 branches. In the red or gem coral (Corallium Linn.) the axis 

 is built up of spiniform sclerites, which are united by a fibro- 

 crystalline calcareous matrix impregnated with organic matter. 

 It occurs only rarely in the fossil state, but is known from 

 the Cretaceous and Tertiary. 



Family 4. Tubiporidae Milne Edwards and Haime. 



Cor alia composed of red-coloured parallel calcareous tubes connected 

 by horizontal plates. 



The cylindrical tubes of the recent Organ-pipe Coral (Tubi- 

 fora) are composed of spiniform sclerites, which are united with one 

 another directly in such manner as to enclose small hollow spaces appearing 

 superficially as pores. The connecting horizontal plates or floors are tra- 

 versed by canals which communicate with the visceral chambers of the 

 tubes by means of numerous round openings. New corallites are budded 

 from their upper surfaces. Unknown in fossil state. 



^ I'oita, Philipp, Sitzuiigsljer. Akad. Wiss. Wien, 1885, vol. .xcii. 



