CORAL BUILDERS. 



23? 



tribute largely to the formation of reefs in the West 

 Indies, they could not be ignored in this chapter,- 

 although their interest is small, as compared with 

 the various forms of Actinoid corals. 



It must, in justice, be remarked here that the con- 

 clusions to which Agassiz arrived have not remained 

 unchallenged. Observations on the same species as 

 that examined by the American zoologist, made by 

 another individual, have led 

 to the adoption of different 

 views, which are thus stated : 

 " The polyp, as seen at Ber- 

 muda in full expansion, is a 

 very remarkable one, and it 

 is a great satisfaction to be 

 able to state that Agassiz 

 saw only a part of the whole, 

 and came to his conclusions 

 too rapidly. The polyps are 

 of different lengths, accord- 

 ing to their growth, are 

 slender, and stand erect in 

 crowds around the branches. 



Each rises from a cylindrical stem, which is ren- 

 dered slightly square close to four tentacles, which 

 project upwards and outwards. Their tips are 

 swollen and rounded, and their bases are con- 

 tinuous, by means of straight dark tissue, which over- 



FIG. 51. 



ZOOIDS OF MILLEPORA. 



