58 Part second. 



Red Sea) stretching often for miles , and several fathoms deep. Their 

 colouring is most exquisite. 



Closely allied to Astroides is Dendrophyllia (Fig. 109), the skeleton 

 of which consists of pure white carbonate of lime and forms large bran- 

 ches. The polypes are of the colour of sulphur and exhibit in the expanded 

 condition a fine ring of tentacles. This species is fairly common on the 

 muddy bottom of the Bay of Naples. 



The branching of the corals takes place by means of the two me- 

 thods of reproduction termed fission and budding respectively. 

 In the case of fission one organism splits into two or more parts, each 

 of which will develop into a new complete individual. This process has 

 often been observed to take place; it has also been successfully brought 

 about by dividing a living animal into suitable pieces, which have then 

 been allowed to grow on and form complete polypes. A similar fission 

 takes place in the case of the Coral-polypes, but with this important dif- 

 ference, that the fission is not complete, but both pieces remain attached 

 at some fixed point. The two individuals form calcareous coverings, which 

 of course remain united the one to the other/Repeating this fission there 

 can arise a colony of corals , and in the course of centuries those im- 

 mense coral-reefs of which mention has been made above. The second 

 and even more rapid process of reproduction is that of budding. In this 

 case the parental polype remains intact, but at one point or other of its 

 body a new growth begins from which, as from a bud, a new individual 

 is formed. This in the case of the Corals does not separate from the first 

 individual but remains attached to it. The whole colony is either suppor- 

 ted internally or surrounded externally by the calcareous framework or 

 covering, which the individuals form themselves ; when they are dead, 

 this retains the appearance of trees or bushes, or assumes other curious 

 shapes. But whatever may be their form or colour, it must always be 

 remembered that these corals are not the coral-animals themselves; 

 they are only the hard, skeletal parks, which have been forme i by mil- 

 lions of small polypes. Of these many hundreds of generations have al- 

 ready died , while their offspring , the present generation , stretch out 

 their delicate tentacles like tiny feathery crowns from the pores of the 

 coral-trees. 



Of these tree-like corals we would mention first the Sea-finger 

 ( deadmen's-fingers ), Alcyonium (Fig. 108), the skeleton of which does 

 not form a united framework , but consists of numerous loose calcareous 

 spicules; so that the animals are able to swell themselves out by taking 

 up a large amount of sea-water. 



The Sea pen , Pennatula (Fig. 110), can also swell itself out at 

 pleasure, by taking in sea-water. When not thus expanded the body is 

 flabby , and the animall to all appearance dead; but when it has taken 

 up sea-water it becomes beautifully transparent and erect, and the leaflike 

 lappets are studded along their upper edge with delicate polypes like 

 transparent flowers. The Sea-pen can move about freely and burrow deep 

 into the sand with its stalk. At night it phosphoresces , when handled 

 roughly, with a greenish light. 



