Growth^ and Habits of Coral Zoophytes. 37 



those that belong to living tissues ; and though differing in 

 different organs according to their end or function, it is all 

 one process, both in nature or cause, whether in the animal- 

 cule or in man. Coral is never, therefore, an agglutination 

 of grains made by the handiwork of the many armed polyps ; 

 for it is no more an act of labour than bone-making in our- 

 selves. And, again, it is not a collection of cells into which 

 the coral animals may withdraw for concealment, any more 

 than the skeleton of a dog is its house or cell ; for every 

 part of the coral of a polyp in most reef-making species 

 is enclosed within the polyp where it was formed by the 

 secreting process.* 



It is important that this point should be thoroughly under- 

 stood, and fully appreciated. That error may no longer be 

 perpetuated, the words polypary and the like, have been 

 rejected by the author in his volume on Zoophytes, and the 

 more familiar term corallum has been used instead-t With 

 this introductory explanation we proceed. 



a. Structure of Coral Animals or Polyps. — A good idea of a 

 coral polyp maybe had from comparison with the garden aster; 

 for the likeness in external form and delicacy of colouring is 

 singularly close. The aster consists of a tinted disk bordered 

 with one or more series of petals ; and in exact analogy, the 

 polyp flower, in its most common form, has a disk often 

 richly coloured, fringed around with petal-like organs called 

 tentacles. Below the disk, in contrast with the slender pedi- 

 cel of the plant, there is a stout cylindrical pedicel or body, 



* It is not perhaps within the range of science to criticise the poet ; yet we 

 may say in this place, in view of the frequent use of the lines even by scientific 

 men, that more error in the same compass could scarcely be found than in the 

 part of Montgomery's Pelican Island, relating to coral formations. The poetry 

 is beautiful, the facts nearly all errors — if literature allows of such an incon- 

 gruity. For ourselves, we think the poet transcends his appropriate limits, 

 when false to nature. 



t See page 15 of the Report on Zoophytes. The term corallium has been 

 set aside by authors because of its being used for a genus of corals. Corallum 

 is an old form of the same word, as particularly explained on the page just re- 

 ferred to, and is not liable to this objection. The true nature of calcareous 

 corals was first pointed out by Milne, Edwards, and Ehrenbeig. 



