60 ZOOPHYTES. 



page, are common about the reefs of the Pacific. They stand on a 

 cylindrical base, which is enveloped in flowers when alive, and 

 consist of a network of branches and branchlets, spreading grace- 

 fully from a centre, covered above with crowded sprigs of tinted 

 polyps. The vases in the collections of the Expedition, at Washing- 

 ton, will bear out this description, although but the lifeless coral. 



The domes of Astrseas are of perfect symmetry, and often grow to 

 a diameter of ten or twelve feet without a blemish. The ruder 

 hillocks of Porites are sometimes twenty feet across. Besides these, 

 we might describe columns, Hercules' clubs, and various strange 

 shapes which are like nothing but themselves. 



56. Each one of these compound zoophytes commenced from a 

 single polyp ; bud followed bud, and so the germ grew up into the 

 coral tree or dome. Calculating the number of polyps that are 

 united in a single Astrsea dome, twelve feet in diameter, each cover- 

 ing a square half inch, we find it exceeding one hundred thousand ; 

 and in a Porites, of the same dimensions, in which the animals are 

 under a line in breadth, the number exceeds five and a half millions; 

 there are here, consequently, five and a half millions of mouths and 

 stomachs to a single zoophyte, contributing together to the growth of 

 the mass, by eating, and growing, and budding, and connected with 

 one another by their lateral tissues and an imperfect cellular or lacunal 

 communication. There is hence every variety, as to number, among 

 compound zoophytes, down to the simple polyp, which never buds at 

 all, and has, for its corallum, a simple calicle ; it may be a tiny 

 goblet, with a stellate cell, as in the Cyathina a cylindrical cup, as 

 in some Dendrophyllias or a radiated disk, as in the Fungias and 

 Cyclolites. 



57. To give a more complete survey of the subject, the following 

 varieties of form are here enumerated. 



1. A simple cylindrical or turbinate calicle : Cyathinae, some Caryo- 

 phylliBe and Cyathophylla. 



2. A simple radiated disk : Fungi*, Cyclolites. 



3. A conical cap, or inverted basin or cup : Polyphylliae, Zoopili, 

 Halomitra, some Fungise. 



4. An upright basin or cup on a short pedicel : some Pavoniae and 

 Manoporse. 



5. Solid hemispherical domes : many Astrsese and Meandrinae. 

 These are sometimes nearly or quite globular. In some Cyatho- 

 phyllidae, these masses consist of separable columns. 



