THE ANNALS 

 MAGAZINE OF NATURAL HISTOilY. 



[SEVENTH SERIES.] 

 No. 62. FEBRUARY 1903. 



XVII. — The Morphologu of the Madreporario, — IV. Fissi' 

 parous Gemmation. By J. E. Dl'ERDEX, Ph.D., A.R.CSc. 

 (Lond.), Bruce Fellow, Johns Hopkins CJniversity. 



Most writers on Madreporarian corals have referred to the 

 occurrence of one or more specially enlarged calices on 

 colonies of which the usual method of vegetative increase is 

 by budding. Thus, while practically all the corallites con- 

 stituting a colony may display, say, twenty-four septa, 

 arranged in two cycles of twelve each, a comparatively few 

 may be found which are much larger than the others, and 

 contain nearly double the usual number of septa. Very 

 rarely one of the enlarged calices may exhibit some stage in 

 the process of fission. The existence of such cases of fission 

 would seem to justify the conclusion that a single species of 

 coral may reproduce both by gemmation and by fissiparity, 

 at one and the same time. 



The influence of these isolated cases of fission on the 

 growth of a gemmiferous colony is manifestly very insignificant, 

 and in systematic studies little or no attention is given to 

 their presence, while no attempt has been made to understand 

 their morphological significance. Thus, Mr. H. M. Bernard 

 (ISOO, p. 491), referring to the claim of Mr. J. J. Quelch 

 that Forites possesses twenty-four septa, remarks : — " These, 

 however, are obviously the large double calicles, one or two 



Ann. dt Mag. N. HisL Ser. 7. Vol. xi. 11 



