INTRODUCTION. lvii 



Second Tribe— MONTIPORIM1. 



Ccenenchyma abundant and spongy. 



9. Genus Alveopora. 



Quoy and Gairnard, Voyage de l'Astrolabe, Zooph., p. 240, 1833. 



Corallum arborescent. CcenencJtyma very porous and echinulate, but not bearing large 

 excrescences. Margins of the calices scarcely distinct. Septa not numerous, and formed 

 by series of spiniform processes. No columella. 



Typ. sp., Alveopora rubra, Quoy and Gaim., loc. cit., Zooph., tab. xix, figs. 11-14. 



10. Genus MoNTiroRA. 



Quoy and Gaimard, op. cit., p. 247, 1833; Manopora, Dana, Zooph., p. 489, 1846. 



Corallum of various forms, differing from Alveopora by the existence of large projec- 

 tions of the camenchyma between the calicules. Ccenenchyma much more abundant, and 

 more delicately spongy. 



Typ. sp., Montipora verrucosa, Quoy and Gaim., op. cit., Zooph., pi. xx, fig. 11. 



11. Genus Psammocora. 



Dana, Zooph., p. 344, 1846. 



Cmnenchyma somewhat compact, of a fasciculate structure, and having its surface 

 papillose. Calices very shallow, confluent, and without distinct walls. Septa thick, and 

 formed by strong spiniform processes. 



Typ. sp., Psammocora obtusata, Dana, loc. cit., p. 345 ; Pavonia obtusangula, Lamarck, Hist, des 

 An. sans Vert., t. ii, p. 240. 



Sub-order 3. 

 ZOANTIIARIA TABULATA. 



Corallum essentially composed of a well-developed mural system, and having the visceral 

 chambers divided into a series of stories by complete transverse tabula; or diaphragms. 

 Septal apparatus rudimentary. 



The principal character of tins sub-order is founded on the existence of the lamellar 

 diaphragms that close the visceral chamber of the corallites at different heights, and differ 

 from the dissepiments of the Astreidae by not being dependent on the septa, and forming 

 as many complete horizontal divisions extending from side to side of the general cavity, 



8 



