POSTLARVAL DEVELOPMENT. 



89 



Within the larger, more vigorous polyps, further calcareous upgrowths 

 began to be formed peripherally during the course of the third week, some 

 appearing as angulated extensions of the primary septa and others wholly 

 independent of them (plate 2, fig. 12). Some of tlie isolated skeletal elements 



I 

 ^ nil X 



/ 



h J 



Fig. 9 (f-j), continued. Serits of diagrammatic figures illustrating the manner of development of the septa from one to three 

 cycles (c/. plates 1-5). The epithcca is shown uniting the peripheral ends of the scpu. 



seemed like short additional septa, situated on different radii from the septa 

 first formed. The new members either retained their independence for a 

 long period or early became fused with the original septum in whose inter- 

 space they had appeared. In this latter instance the original septum was 



