34 TABULATE CORALS. 



The zoological affinities of the Favositidce > as has been seen, 

 are with the Zoantharia Perforata, and the family may find a 

 place close to the Poritidce. The typical genera of the Favo- 

 sitidce (Favosites, Lam., Alveolites, Lam., Michelinia, De Kon., 

 &c.) are distinguished from the typical Poritidce by the much 

 more complete development of the walls of the corallites, by 

 the reduction of the channels of communication between the 

 visceral chambers of contiguous polypes to comparatively 

 minute and for the most part serially-arranged " pores," and 

 by the presence of well -developed tabulae. On the other 

 hand, the Cretaceous Koninckia, E. and H., and the Devonian 

 Arczopora, Nich. and Eth. jun., have the walls so highly cribri- 

 form and the tabulae so greatly reduced that they might per- 

 fectly well be placed in the family of the Poritidce. in the 

 vicinity of the recent Alveopora, Quoy and Gaim. (fig. 13), and 

 Favositipora, Sav. Kent. The link between these extreme 

 forms is effected by such a type as the Lower Silurian Colum- 

 nopora, Nich., which has highly but regularly perforated walls, 

 combined with numerous complete tabulae and lamellar though 

 rudimentary septa. Another group of the Favositidce is con- 

 stituted by Pachypora, Lindstrom, Striatopora, Hall, Trachy- 

 pora, E. and H., Dendropora, Mich., and Ccenites, Eichw. in 

 all of which the cavities of the polypes are more or less con- 

 tracted by the deposition of sclerenchyma on the interior of 

 the walls of the corallites. Many of these forms consequently 

 assume an appearance extremely similar to that of the recent 

 Pocillopora, Lam., and Seriatopora, Lam., from which, however, 

 they are fundamentally separated by the absence of a ccenen- 

 chyma and by their perforated walls. The genus Stenopora, 

 Lonsd., though possessing peculiarly thickened walls, exhibits 

 so many other anomalous features that it cannot be associated 

 with the preceding, but must rather be regarded as a special 

 type. The genus Syringolites, Hinde, though in many re- 

 spects entirely like a Favosites, possesses funnel-shaped tabulae, 

 which give rise to an axial tube in the centre of each corallite 

 thus forming an interesting link between the Favositidce and 



