Vol. 69.J 



THE 6ENTJS AVLOPHYLLUM. 



61 



as the coral developed. 



Pig. 3. — (After CarriitTiers.) 



1 ' Beitriige zur Kenntniss fossiler Korailen 

 Gesellscb. vol. xxi (1869) p. G47. 



Thus new septa appeared at both sides of 

 the cardinal septum and immedi- 

 ately behind the alar septa, and 

 three breaks or fossulae were 

 formed. The pinnate plan out- 

 lined by Kunth was thus designed. 1 

 As this insertion of secondary 

 septa took place, the alar septa 

 moved round until they occupied 

 a position approximately 80" 

 from the cardinal septum, and 

 the counter-lateral approached the 

 counter-septum until the space 

 between it and the former cor- 

 responded to other interseptal 

 spaces. The present investigation 

 has shown, however, that the first 

 four secondary septa were not 

 formed simultaneously, but those 

 which originated at the alar fos- 

 sulae appeared first. These were 

 followed by the two in the car- 

 dinal fossula. This order of the 

 insertion of secondary septa was 

 continued throughout the growth 

 of the coral, and is illustrated 

 in the diagram (fig. 5) ; 2 a 

 and 2 a appeared before 2 c and 

 and a' being those ori- 

 ginating at alar fossuloe and c and 

 (•' those at the cardinal fossula), 

 3 a and 3 a' before 3 c and 3 c . . . 

 and n a and n a' before 

 n c and "c ; in some 

 cases, however, more 

 than one extra pair 

 was added at the alar 

 fossula;. The result- 

 is that, except where 

 irregularities occur, 

 there are at least 

 two more septa in the 

 counter-septal quad- 

 rants than in the 

 cardinal quadrants. 

 In other words, there 

 are two or more septa 

 of alar-fossuke origin 

 more than of cardinal - 

 fossula source. 

 Zeitschr. Deutseh. Geol. 



