﻿MORPHOLOGY OF CORAL POLYPS 



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the end, when a double series of mesenteries has appeared, including 

 two pairs of directives, the stomodaeum divides, and half the mesen- 

 teries are apportioned to each. The process has been termed 

 fissiparous gemmation. Instances of it occur on most gemmiferous 

 colonies, but hitherto its significance, as contrasted with ordinary 

 fission and gemmation, has not been understood. 



SEXUAL REPRODUCTION 



Coral polyps in general seem to be hermaphrodite, both ova and 

 spermaria occurring on the same or separate mesenteries. Whenever 



W. JSL 



IE IE 



HI 



Fig. 10. — Four diagrammatic figures showing the order of appearance of the 

 six primary pairs of mesenteries. In a only two pairs of mesenteries are pres- 

 ent, of which one pair (1) is united with the stomodaeum, while the other (11) 

 is free; in b the second pair of mesenteries has become complete, and a third 

 pair (in) has appeared on the ventral border; in c another pair (iv) is found 

 within the dorsal chamber; in d the first four pairs of mesenteries to arise 

 have all become complete, and the fifth and sixth pairs (v, vi) have appeared, 

 but remain incomplete for a long period, the secondary mesenteries appear- 

 ing in the meantime (cf. figure 11). The actual stages given are taken from 

 Manicina areolata, but a like sequence is presented by other species whose 

 development has been followed. 



