132 MADREPORARIA. 



P. St. Thomas 7. Creeping (?). 



P. Bahamas 1. With thin edges, which sometimes thicken rapidly. 



P. West Indies x. 26. Lamarck's original " P. astrwoides." 



P. West Indies x. 27. With segmentation disguised. 



P. West Indies x. 30. (= " Neoporites littoralis," D. and M.). 



C. Massive. 



We have already noted the very natural confusion which has attended the use of this 

 term. In those cases in which the consecutive growths are very distinct and show great 

 numbers of edges, tliere has been a tendency to speak of it as "encrusting," because its 

 construction out of a pile of layers is apparent. While those forms in which the consecutive 

 growths droop so as to cover the edges of previous layers are called massive, it seems clear 

 that if we wish to call attention to the differences in our choice of names, such terms as 

 massive and encrusting are not calculated in any way to express what we wish to emphasise. 

 Botli forms are massive, and what we want to express is that the growth segments of the one 

 are pronounced and of the other disguised. This disguising is most complete when the 

 corallum is a globular mass, each growth completely enveloping the whole. Such a form 

 appears to have grown from the first as a single homogeneous mass, and further, the first 

 glance of its section shows the same, an expanding bundle of continuous trabeculae. But a 

 comparative study of growth processes shows that this is only an extreme specialisation ; it 

 cannot be regarded as any exception to the rule of growth of the Stony Corals, even if no 

 tabulae could be found, but tabulae are found, and tell the same tale as bands of epitheca 

 round edges, for these two features are parts of one and the same structure.* 



P. Brazil 1, = the " P. solida " of Verrill, described as " encrusting " or " massive ! " 



P. Trinidad 1. Only known in fossil fragments. 



P. Barbados 9. „ „ 



P. Guadalupe 6, compared with " P. conglomerata " Esper t and with surface raised 



into round lobes. 

 P. Antigua 4. Segmentation obvious (see above B, V). 



P. Porto Rico 5. Segmentation disguised, a typical specimen of " Astrceoides " autorum. 

 P. Porto Rico 6. „ „ „ 



P. St. Domingo 1. „ „ „ 



P. Belize 2. 



P. Belize 3. „ „ „ 



P. Florida 6. „ ' „ „ 



P. West Indies x. 28 „ „ „ 



P. West Indies x. 29 „ „ >, 



As already pointed out in the text p. 15, these " Porites astrceoides," that is those massive, or 

 thick encrusting forms in vjhich the growth segments are disguised — cannot justly be regarded 

 as one and the same species, because differences appear which seem to be fundamental. I refer 



• The case of I'. China Sea H. (Vol. V. p. 177), is worth recalling. There were apparently 

 two specimens, one thin encrusting, and the other a huge mass built up of piles of such stocks. I 

 was at the time much puzzled as to the description of its growth-form. 



■f Pflaiizentb. Suppl. i. pi. 59a. (See above, p. 114.) 



