GENERA OE EAVOSITIDyE. 131 



the corallum, but immensely thickened in the neighbourhood of 

 their mouths by means of a dense secondary deposit of scleren- 

 chyma, the proper walls nevertheless always remaining distinct. 

 Visceral chamber reduced to a fissure in the vicinity of its termi- 

 nation, and opening upon the surface by a narrow transversely- 

 elongated slit-like calice, one lip of which carries two tooth-like 

 projections, which face a single similar tooth springing from 

 the opposite lip. Septa represented only by the calicine teeth 

 just spoken of. Tabulae well developed, complete, horizontal. 

 Mural pores moderately numerous, large-sized, irregularly dis- 

 tributed. 



Obs. — The genus Ccenites was originally founded by Eich- 

 wald {loc. ciL), and was subsequently described by him 

 (Letha^a Rossica, vol. i. p. 457) as comprising dendroid or 

 lamellar and encrusting corals, with semicircular or triangular 

 calices, provided with a single rudimentary septal ridge upon 

 their lower lips, the corallites being united by an abundant 

 " ccenenchyma." Milne-Edwards and Haime (Pol. Foss. des 

 Terr. Pal., p. 301) also suppose that a "ccenenchyma" is pre- 

 sent, and they describe the septal system as consisting typically 

 of three teeth, two on one margin of the calice and one on the 

 other. The same authors include the genus among the Pocil- 

 loporidiE, though they subsequently express a doubt whether it 

 should not rather be removed from the Actinozoa and placed 

 among \h& Polyzoa (Brit. Foss. Cor., p. 276). Professor Martin 

 Duncan (Third Rep. on Brit. Foss. Cor. ; Rep. Brit. Ass., 

 1871, p. 130) also assumes the existence of a "ccenenchyma" 

 in Coenites. Dr Lindstrom (Nigra Anteckningar om AntJiozoa 

 Tabulata, Ofversigt af Vetensk. Akad. Forhandl., 1873) con- 

 siders that Coenites may possibly be referable to the Polyzoa ; 

 but, somewhat inexplicably, he regards Alveolites suborbicularis, 

 Lam., and its allies as belonging to this genus. Mr R. Ethe- 

 ridge, jun., and myself pointed out (Journ. Linn. Soc, vol. xiii. 

 p. 361), from an examination of Cmiitcs orientalis, Eichw., that 

 probably there existed no true ccenenchyma in Ccenites, and in- 

 dicated that this generic name might need to be suppressed in 



