CORALLINES. 



135 



Fig. 56. A young Coral Polyp fixed upon a 

 Kock. (Lacaze-Duthiers.) 



all young, and indicating the definite form of development which the 

 collective beings are to assume. 



The simple isolated state of 

 the animal, whose phases of de- 

 velopment we have indicated, 

 does not last long. It possesses 

 the property of producing new 

 beings, as we have already said, 

 by budding. But how is the 

 polypidom formed ? If we take 

 a very young branch, we find in 

 the centre of the thickness of 

 the crust a nucleus or stony 

 substance resembling an agglomeration of spicula. When they are 

 sufficient in number and size, these nuclei form a kind of stony plate, 

 which is imbedded in the thickness 

 of the tissues of the animal. These 

 laminee, at first quite flat, assume 

 in the course of their development 

 a horse-shoe shape. Figs. 59 and 

 60 will give the reader some idea 

 of the form in which the young 

 present themselves. Fig. 59 repre- 

 sents the corpuscles in which the 

 polypidom has its origin ; Fig. 60, 

 the rudimentary form of the coralline polypidom. 



Our information fails to convey any precise notion of the time 

 necessary for the coral to acquire the 

 various proportions in which it pre- 

 sents itself. 



Darwin, who examined some of these 

 creatures very minutely, tells us that 

 " several genera (Flustrse, Escharae, 

 Cellaria, Cresia, and others) agree in 

 having singular movable organs at- 

 tached to their cells. The organs in 

 the greater number of cases very closely resemble the head of a 

 vulture ; but the lower mandible can be opened much wider than a 



57. Young Coral Polyp attached to a 

 Kock and expanded. (Lacaze-Duthiers.) 



Fig. 58. A Rock covered with young Polyps 

 and Polypidom. (Lacaze-Duthiers.) 



