TAMILIES AND GENEEA OF THE MADEEPOEAEIA. 47 



Moseley (Quart. Journ. Micr. Sci. Ixxxviii. p. 391, " Notes on 

 the Structure of Seriatopora,^^ &c.) states that Seriatopora is 

 Madreporarian. The polyps bear twelve short tentacles with 

 rounded knobs in two series. The carities of the polyps are in 

 communication by means of a canal-system forming a network, 

 which traverses the entire area at the surface between the polyps. 

 The polyps of Seriatopora and Pocillopora possess only a single 

 pair of long mesenterial filaments, and these belong to the central 

 mesenteries, of the lateral chambers. Both of the genera differ 

 from other Madreporaria in not having their mesenteries arranged 

 in pairs. 



Genus Pocillopora, Lamarck & Verrill. 

 Grenus Seriatopora, Lamarck. 



Genus Pocillopoka, Lamarch (pars) ; Verrill, Notes on 

 Madiata, p. 519 (1870). 



Colony of clusters of branches, or lobes, or fronds of various 

 dimensions, which arise from a more or less compact incrusting 

 base. Branches often with rudimentary branchlets or verrucose. 

 Corallites crowded terminally, angular, and closely united by their 

 walls ; on the sides of branches they are more or less separated 

 by compact coenenchyma which is sharply spinulose or granular. 

 Calicos small, may be deep or shallow, circular or angular, often 

 filled, below the surface, by a solid deposit. The corallites are 

 crossed by tabulae. Septa narrow, often rudimentary, especially 

 in the crowded calicos at the ends of branches, in others longer, 

 usually twelve in number, six larger than the others. Columella 

 when present small, solid, little prominent on the upper tabulae. 

 Tabulae often incomplete in middle . Increase by gemmation. 

 Fissiparity very rare. Polyps with 12 tentacles, and a single 

 pair of long mesenterial filaments. 



Distribution. — Fossil. Miocene : "West Indies. — Becent. Pacific, 

 Indian Ocean, Eed Sea. 



Grenus Seeiatopoea, Lamarck, Sist. Anim. sans Verteb. t. ii. 

 p. 282 (1816). 



Colony arborescent. Coenenchyma compact and abundant, 

 finely echinulate. Calicos placed in ascending series. Septa 

 rudimentary and barely visible. Columella large, compact. 



