128 ME. H. M. BEEKAED ON EECEKT rOEITIB^. 



are, in fact, little more than surface depressions ia a skeletal 

 mass, conspicuous on account of its being a fine porous 

 reticulum. The shallow calicles may be rounded and separated 

 bj reticular walls of different thicknesses, or else so crowded 

 together as to be polygonal in outline. The skeletal structure 

 within the calicle is also remarkable. The radial symmetry, 

 which is such a striking feature in the Stony Corals, is in Porites 

 more or less obscured. Septa never stand out as radiating plates, 

 but instead 5-6 or more rod-like or granular pali rise up as 

 a central ring from the reticulum which fills up the base of 

 the calicle. Eound this ring of pali the rudiments of septal 

 formation can generally be traced. 



Such corals as these early attracted the attention of naturalists, 

 and the significant name Porites was first associated with them 

 by Pallas (1766), and was eventually accepted by Lamarck as 

 the generic name. 



The position which Lamarck assigned to the new genus is 

 given in his classification of the " Lamelliferous " Corals (Anim. 

 s. Vert., ed. 1816, ii. p. 219). It is placed with Madrepora in 

 the last section, viz., in that which contained corals with cells 

 circumscribed and covering the whole free surface of the stock, 

 and it follows Astrcsa, which also has cells circumscribed but 

 confined to the upper surface of the stock. 



In 1821 * Lamouroux followed Lamarck in placing the genus 

 Forites after Astraia, but called the group in which the former 

 occurred "Les Madreporees," and that in which ^s^r<»ff occurred 

 " Les Astrees." De Blainville t divided the Stony Corals into 

 " Madrephyllies " and " Madrepores," the Astrgeids being placed 

 among the former and Porites near the end of the latter. 

 Nevertheless, in his observations he admits the apparent kinship 

 of the genus with both Astrcea and Madrepora as suggested by 

 Lamarck, but thought it was much closer with the latter than 

 with the former. The recently established genus Croniopora, 

 Q. & G., was rightly placed by De Blainville next to, but iii front 

 of, Porites. 



In 1834 EhrenbergJ placed Porites in the " Madreporina,'- 

 which Mere quite distinct from the " Astrgeina." The Madre- 

 porina were divided mainly according to their methods of 



* ' Exposition Methodique,' pp. 56, 60. 



t ' Manuel,' pp. 334, 395. 



I ' Corallenthiere des Eothen Meeres,' pp. 91-115. 



