12 MADREPORAKIA. 



the basis of a practical unit. The only real units presented to us by nature, are the local 

 forms. I have attempted to begin the work again with these, hoping that little by little we 

 shall discover their inter-relationships. And, as their method of designation, I name the units 

 after their localities, and am disposed to assume that, just as these can be indicated by the 

 localities in which they occur, so their larger groupings based upon discovered relationship will be 

 ultimately expressible — at least for purposes of reference — in terms of larger geographical areas. 

 Morphological names being too crude and misleading, is seems to me that the local 

 names so admirably indicate the only known and certain fact whicli distinguishes one 

 member of the genus from another that it would be nothing short of a wilful obscuring 

 of those facts to give the forms any other designations than those of the places where they 

 occur. I am convinced that, as ah-eady stated above, p. 2, we shall have to begin our 

 attempts to classify Corals as we first attempt to classify the human race, calling the units 

 simply English,* Arabian, Chinese, etc. after the places they inhabit and from which they have 

 spread. 



III. MORPHOLOGICAL. 



We have already mentioned the fact that the Atlantic and West Indian Pontes form 

 a group apart from that — or those — of the Indo-Pacific. A certain homogeneity characterises 

 the former which at once strikes the eye as soon as any large collection is examined. To be 

 able to notice it is, however, one thing : to describe it is quite another. This was indeed one of 

 the problems we set ourselves to try to do, namely, to run down, by analysis, the secret of that 

 subtle facies which differentiates the West Indian Pm-ites from those of the rest of the world. 



Whatever it might be, it presumably finds expression in three ways : — 



1. There is a strange stifihess in the growth-forms, hitherto thought to present only two 

 kinds, encrusting, and more or less freely branching. Although this is far too limited a 

 description for the whole of the facts, yet the stiffness and want of plasticity of the West 

 Indian Porites as compared with those of the Indo-Pacific region is quite startling. 



2. There is an almost complete absence of any form which we could, unhesitatingly, call 

 coenenchymatous (see e.g. PL V. fig. 3). Such forms are especially numerous, and very highly 

 specialised, among the Indo-Pacific Pontes. See the list given in Table IV. Vol. V. p. 274. 



3. There is a boldness and irregularity in the arrangements of the calicle skeletons very 

 different from the delicacy and often perfect symmetry shown in the calicles of many Indo- 

 Pacific forms. In spite of the almost innumerable variations of the latter, they hardly ever 

 show calicles characteristic of the West Indian foims ; while again, the calicles of the former 

 are, on the average, larger than those of the latter. 



When these differences are brooded over, they loom at first very large, and a vague sugges- 

 tion that the forms of the two regions should be treated as sub-genera haunts the mind of 

 the student. In this case, however, it was not listened to, because of the fact that the 

 fundamenUl morphological analysis shows the two to be the same in every feature of structural 

 importance. 



• [See, however, Huxiey, 'Forefathers of the English People,' Nature, i. (1870) p. 514.— Ed.] 



