370 



THE INHABITANTS OF THE SEA. 



Tubipora Musica. 



and is frequently found in cabinets of natural history, the horny 

 and calcareous matter of the axis is disposed in alternate joints^ 

 so as to unite flexibility with firmness. A similar structure of 

 alternately disposed calcareous and horny segments occurs in 

 Mopsea. In Isis branches are developed from the calcareous, 

 in Mopsea from the horny segments of the axis. 



The Tubiporidse are confined to the narrow limits of a single 

 genus containing but few species. Here the polypary is com- 

 posed of distinct calcareous tubes 

 rising from a fleshy or membrana- 

 ceous basis, and arranged in suc- 

 cessive stages. These tubes are 

 separated from each other by 

 considerable intervals, but mutu- 

 ally . support each other by the 

 interposition of external hori- 

 zontal plates, formed of the same 

 dense substance as themselves, by which they are united to- 

 gether, so that a mass of these tubes exhibits an arrangement 

 something like that of the pipes in an organ, whence the 

 beautiful Indian species, Tubipora musica, has derived its" 

 name. From the upper ends of the tubes the polyps are 

 protruded, and being, when alive, of a bright grass-green 

 colour, they contrast very beautifully with the rich crimson oi 

 the tubes they inhabit. 



In our seas, the coralligenous Zoophytarians, distinguished by 

 the hard calcareous skeletons they deposit within their tissues 

 are but feebly represented by a few straggling Caryophyllise, but 



in the tropical ocean they branch out 

 into numerous families, genera, and 

 species, and play a highly important 

 part in the economy of the maritime 

 domain. Originally proceeding from 

 single ova, which at first freely move 

 by means of vibratile ciliffi, and 

 become fixed after a short period of 

 erratic existence, they multiply by gemmation, and grow into 

 an immense variety of forms, of which the following descrip- 

 tion by one who has long and attentively studied them in their 

 native haunts may serve to give an idea. "Trees of coral," 



Caryophyllia. 



