CORAL-MAKING AUTINOID POLYPS. 57 



mouth has its own circle ; and in the third, the separation has 

 gone so far as to complete the circles and make two independ- 

 ent polyps. This dividing one 1 s self in two, for the sake of an 

 increase of population, is the process called spontaneous fis- 

 sion or fissiparity. 



This mode of budding does not belong exclusively to coral 

 polyps, for it has been observed among a few Actiniae. Gosse 

 describes its occurrence in a British species, the Anihea cereus, 

 in which it results in two distinct animals. He says "the 

 fission begins at the margin of the disk, and gradually extends 

 downward until the separation is complete, when each moiety 

 soon closes and forms a perfect animal." 1 The same author al- 

 ludes to the occurrence of double-disked individuals of the gen- 

 era Actinoloba, and Actinia as illustrating the process without 

 a separation of the spontaneously developed pair. 



This spontaneous fission is the common kind of budding 

 in the large Astraea tribe. 



ASTILEA PALLIDA, D. 



The preceding figure represents a species of living coral of 

 the Astraea family, from the Feejees, the Astrcea pallida D. 



