MADREPORARIA APOROSA. 275 



are very numerous and are arranged in several cycles, their inner edges 

 being dentate and giving rise superiorly to an irregular pseudo-colu- 

 mella. The septa are not alternately equal, and the symmetry appears 

 to be completely radial. Endothecal tissue is largely developed, the 

 dissepiments being vesicular in the periphery of the visceral chamber, 

 but uniting to form distinct tabulae centrally. In the possession of 

 an exterior vesicular zone and the presence of a central tabulate area, 

 the genus Moseleya resembles the extinct genus Cyathophyllum ; and 

 it is referred by Quelch to the family Cyathophy Hides. Upon the 

 strength of this resemblance, indeed, the authority just mentioned 

 refers the Cyathophy Hides, along with the remaining corals usually 

 grouped under the head of Rugosa, to the division of the Madre- 

 poraria Aporosa. It is possible that future researches may justify 

 the merging of the Rugosa in the Aporosa, but it does not appear 

 in the meanwhile that there is sufficient evidence to warrant a change 

 so sweeping. Even as regards the genus Cyathophyllum itself and 

 its immediate allies, the resemblances to Moseleya are not without 

 noteworthy counterbalancing differences, as, for example, the general 

 bilateral symmetry of the former, and the usual development of the 

 septa in a pinnate manner along three principal lines. Still more 

 weighty, of course, are the differences which separate the Zaphren- 

 toidea and the Cystiphylloidea from Moseleya. Upon the whole, 

 therefore, as will be more fully shown in what follows, there ap- 

 pears to be sufficient ground for the retention of the Rugosa as a 

 special division of the Madreporaria, though certain of the Rugose 

 corals of former writers may well be placed among the Aporosa. 



