12 MADREPORARIA. 



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

 forms. I liave 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 tliat, just as these can be indicated by the 

 localities in which tliey occur, so tlicir larger groupings based upon discovered relationshi]) will be 

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

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

 names so admirably indicate the only known and certain fact which 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 already 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, Clunese, etc. after the places they inhabit and I'roni which tlicy have 



III. MORPHOLOGICAL. 



We have already mentioned the fact that the Atlantic and West Indian Foj'itcs form 

 a group apart I'rom 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 om^selves to try to do, namely, to run down, by analysis, the secret of that 

 subtle facies which differentiates the West Indian Pontes from those of the rest of the world. 



Wliatever it might be, it presumably finds expression in tlii-ee ways : — 



1. There is a strange stiffness 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. PI. V. fig. 3). Such forms are especially numerous, and very highly 

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



3. There is a boldness and UTegularity 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 forms ; wliile 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 Ibrms 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 

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

 importance. 



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



