190 ACTINOZOA. 



7. The degree and nature of the union between 

 the several corallites ; whether this be pro- 

 duced by the close contact and blending of 

 their walls, or by the development, both in 

 a horizontal and vertical direction, of an 

 epitheca, coenenchyma, and other similar 

 structures {fig. 33): 

 and several less essential modifications of the same 

 process, manifested either separately or in com- 

 bination. 



It is, therefore, not surprising to find among 

 budding Corals forms analogous in every respect 

 to those produced by fission and, in addition, many 

 others whose physiognomy, copious as is the list of 

 descriptive terms, it is scarcely possible to define. 

 Nor does each Coral always restrict itself to a 

 single mode of growth, but, on the contrary, 

 several kinds of gemmation, or of gemmation 

 and fission in unison, have been observed to take 

 place in the same species. So that, even with the 

 aid of figures, and extensive suites of museum 

 specimens, the development of the composite 

 Corals can receive illustration in but a limited 

 and im.perfect degree. For these organisms, like 

 all others, rightly to be understood, must be 

 studied amid " the glorious variety of Nature " 

 itself, "living and multiplying in their destined 

 homes and habitats." 



Mr. Dana, who devoted much time to the exami- 

 nation of the Corals of the Pacific, thus endeavours 

 to describe some of their general diversities of 

 form : 



" Trees of coral are well known ; and although 

 not emulating in size the oaks of our forests, — 

 for they do not exceed six or eight feet in height. 



