10 MADREPORAEIA. 



arbitrary to crush so many structural differences into two species with such apparently 

 small differences between them. An examination of the specimens in the U.S. National 

 Museum showed Dr. Gregory that the supposed distinctions between P. clavaria and P. furcata 

 were quite worthless. The natural conclusion, therefore, was that these two imaginary species 

 had to be amalgamated as one, and, apart from the gradual accumulation of. facts, which is 

 valuable for all time, the work on the West Indian Pontes had culminated in an imaginary 

 proof that all the branching West Indian Porites were of one and the same species, and that 

 that species had as its type the specimen from some unknown locality, and, I might almost 

 say, with unknown calicle structure, which fell accidentally into Lamarck's hands, and was 

 called by him P. clavaria ! 



This surely has the merit of " conclusiveness," not, however, as regards the systematics of 

 the West Indian Porites, which was the subject in hand, but, at least it is to be hoped, as 

 regards the method. It is obvious that the mere statement that all the many branching forms 

 are all one species, which we should call clavaria, and that all the encrusting forms constitute 

 a second species, which should be called astrceoides, is totally without value. On its positive 

 side it merely affirms that they are all related genetically, which is already connoted by classing 

 them in the same genus ; and on its negative side it denies the existence of any striking 

 structural variations of specific value, a useless denial, because nobody knows what a "species" 

 means, nor consequently what is the meaning of a " specific difference." We must refer the 

 reader to the morphological section for an account of the structural differences revealed during 

 the study of the forms for this Volume. He will find them both more extensive, in that the 

 two obvious divisions into brandling and encrusting is far too crude, and more striking than 

 was supposed, supplying us with every indication that the future will reveal a wealth of 

 variation hitherto undreamed of. 



All then that has been attained by working for nearly a century with imaginary species, 

 has been the conclusion that there are not three imaginary species, but two, which being also 

 imaginary, leaves the simple facts just where they were. I am aware, of course, that it may 

 be argued that, inasmuch as Porites clavaria and furcata were at any rate representatives of 

 local forms, they were not wholly imaginary — not so imaginary, in fact, as P. arenosa (see p. 112) 

 and P. incrustans (see Vol. IV. p. 117). That is true, and we have already dealt with that subject 

 above, p. 5. But what are we to say of the use of the names clavaria and furcata as if they 

 represented wide-spread, well-known species, while hardly a soul who used them had a chance 

 of carefully studying and comparing them with the types regarded as local forms ? They need 

 not have been imaginary quantities, but they were so, inasmuch as no trustworthy figures * 

 and no morphological diagnoses were available, and their localities were unknown ; and without 

 any of these they were empty names. 



Only one writer has taken the subject in hand since Dr. Gregory showed that the old 



• Except the one above referred to (p. 6) of Milne-Edwards and Haime, which, for reasons 

 explained, appears to have been little consulted. 



