78 



ZOOPHYTES. 



Fig. 39. 



uninterruptedly from one polyp-centre to another. If the polyp-disks, 

 therefore, should be coalescent in a plane in all directions, instead of 

 in simple meandering lines, there would be no proper interstices 

 between the polyps, and no cells, and the lamelte would be con- 

 tinuous in every direction, from one centre to another. It hence 

 appears, that the peculiarities of the Fungidse consist in the absence 

 of all interstices between the stars, and a uniform continuation of a 

 single compound disk-surface over the whole. The process of budding, 

 therefore, although seemingly like that of the Echinopora, is actually 

 identical with that of the Merulinae, in which buds open in the extend- 

 ing disks. The compound free Fungidse, the Agariciae, the Pavonse, 

 are equally good examples of the characters here explained. In the 

 Polyphyllise, the union of adjacent polyps is so close, that there is 

 not even a separate series of tentacles to each polyp-mouth, and this 

 character separates these species from the allied Herpetolithi. 



79. Modes of branching. In species of Astraida3, which form cali- 

 cularly-branched coralla, the disks widen and subdivision takes place 

 as in the Astrsea above explained, except that the subdivision con- 

 tinues in progress until the two polyps are 

 distinct at base, and each forms a separate 

 branch. The annexed figure represents the 

 whole process. On one branch, two polyp- 

 mouths already exist in the enlarged disk, 

 and at the extremity of the other, furcation 

 has commenced ; the furcation seen below, 

 is an example of the subdivision completed. 

 The difference between separation by this 

 divergent growth, and the spontaneous fission 

 of a monad, is obvious. The MussaB, Eu- 

 phyllia3, Caulastra383, grow, and bud, and 

 branch, in this manner ; and the process goes 

 on so regularly that the zoophytes are usually 

 perfect hemispheres; the size of the branches, 

 their length before furcation, and the intervals 

 between them, being very uniform in the same 

 species. 



This mode of branching by furcation is analogous in many respects 

 to that which proceeds from the growth of a budding-cluster. 



b. Branches also form by a successive accumulation of buds, nearly 

 as in the OculinaB. The foliaceous species result from prolate growth, 



