rnMI'AKATlVK ANAT<>MY. 



185 



VI. 



LAB CORAL ISLAND, WITH 



of lime is associated with the tendency to grow, and branch, 

 and bud, which we have remarked in the Hydrozoa, the two 

 united teudenoiea produce those most beautiful forms we call 

 coral*. Very various are the forms assumed by ooralti. One 

 is called Funjin Ayuricifurmis, or the mushroom-like coral, 

 on account of it* rewmblanoe to that fungus. The likeness, 

 however, it 



to - I-TMMI"^ 



the 



mushroom 

 would be if 

 deprived of 

 its stalk 

 and the 

 upper part 

 of its dome, 

 than what 

 it really is. 

 Another is 

 called the 

 brain coral, 

 from the 

 very much 

 closer re- 

 semblance 

 which it 

 bears to the 

 brain of a 

 man, being 

 grooved 

 into sinuous 

 channels 

 just like 

 those chan- 

 nels which are called the convolutions of the brain. Other forms 

 are branched like a stag's horn, or spread out like a fan. A 

 thousand different modifications are found, but each is made up 

 of almost the same elements. Each element is almost identical 



with the hard part 

 of the little English 

 coral represented in 

 the engraving (Fig. 

 II.) as stripped of its 

 soft parts. Each con- 

 sists of an outer cup 

 with plates deve- 

 loped from its walls, 

 and stretching in- 

 wards as they grow 

 towards a central 



part, where, when the soft parts existed, the stomach was situ- 

 ated, lying immediately under the central mouth. The great 

 specific differences are the results of the manner in which bud- 

 ding takes place from the original parent element : as, for in- 

 stance, whether the buds spring from the 

 side wall, or from the disc between the 

 mouth and tentacles ; whether a great 

 many are formed at the same time, or only 

 two, or one, at once ; whether they sprout 

 out at a small or large angle, etc. etc. 



All the forms hitherto referred to be- 

 long to one order called the Zoanthoria, 

 or animal flowers. These are the only 

 corals which have stony partitions deve- 

 loped from those membranes which, run- 

 ning from the stomach wall to the body 

 wall, are called septa. A curious numeri- 

 cal law applies to these septa. However 



many of them there may be, and there are sometimes hundreds 

 of them, they always are in some multiples of 5 or 6. This 

 is always true, although their numbers are continually in- 

 creasing as the animals develop in size. This results from 

 the fact that in those animals where, for instance, 6 is 

 the dominant number, whenever one new septum is developed 

 it is always accompanied by five others at least, or if more 

 than five then eleven others, making six or twelve in all. 

 In the first instance, six are developed at equal distances 

 round the wall. These six compartments are, in the next 



VII. 



REEFS. 



Barrier * Beef. 



IX. FORMATION or ATOLL. 2. 



stage, each divided by x other sept*. Then the twelve 

 new compartment* so formed are divided by the development 

 of twelve new septa. At this stage it seem* M though the ani- 

 mal, seeing no end to this kind of multiplication, refused to 

 develop more than twelve at a time, so that all the chambers 

 cannot be bisected at once, but only some of them. Nererthe- 



leas, so re- 

 gular are 

 the vital 

 forces in 

 their action 

 that M. 

 Milne Ed- 

 wards ha 

 given a 

 number of 

 laws by 

 which it 

 may be 

 predicted 

 where the 

 next septa 

 will appear. 

 These laws 

 are too com- 

 plicated to 

 be given 

 here. If 

 the reader 

 should be 

 fond of wan- 

 dering at 

 the edge of 

 the sea at 



ebb tide, in many parts of our coasts he will be almost sure 

 to find some orange or yellow masses whose size and form 

 will remind him of the roots of ginger. The livid appearance 

 of these, together with their soft fleshy feel, has earned for 

 them the cognomen 

 of dead-men's fin- 

 gers. If, however, 

 these be placed in 

 an aquarium, they 

 put out, from all 

 parts of their sur- 

 face, little flower- 

 like heads. Each 

 of the heads is 

 crowned with eight 

 tentacles arranged in the form of a star, and each of these is 

 fringed with secondary tentacles. In most other respects they 

 resemble the Zoanthoria, but they are cut off from them by 

 two other marked differences. All their parts are in mul- 

 tiples of 4, and their membraneous partitions never secrete 

 hard septa. Sometimes, however, they 

 develop tubular coralr, which after bud- 

 ding from a common stock send out from 

 the outsides of these tubes lateral plat- 

 forms, which unite and support the seve- 

 ral tubes. The parallel tubes so sup- 

 ported look not unlike organ pipes, or 

 those reed instruments which are fixed 

 under the mouth of that musician who so 

 generally accompanies Punch and Judy. 

 In consequence of this resemblance the 

 animal which forms them is called Tubi- 

 porn musicu. 



The more general habit, however, is 



for the animals to secrete from their bases only. Never- 

 theless, this secretion is so managed as to raise the compound 

 animal from the rock on which it grows. These animals put 

 forth buds from the circumference of their basal discs, and 

 thus a number of these polypes are placed horizontally with 

 their bases united, so as to enclose an elongated hollow in 

 which they secrete the dense, hard, and sometimes beautiful and 

 branching coral. The red coral obtained from the coasts of 

 Italy, which is so much prized for the manufacture of orna- 

 ments, is of this nature. Another family of the same order pro- 



Vin. FOKMATIOK or ATOLL. 1. 



