PORITES. 9 
(6) Synarea. 
This genus was founded to include those forms described by Dana among his Porites, with 
regard to which Milne-Edwards and Haime had expressed doubts in their “ Monographie des 
Poritides,” by notes of interrogation. These doubts were repeated by Milne-Edwards in 
the third volume of “Les Coralliaires” in 1860. Acting apparently on this suggestion, 
Dr. Verrill * described the new genus as follows :— 
The corallum is irregularly branched or glomerated, the cells without distinct walls, the 
septa rudimentary. Six prominent paliform lobes surround the central cavity, which has a 
rudimentary or very small trabecular columella ; outside of the pali are other similar points 
or granulations scattered between the cells which are not distinctly circumscribed, but often 
separated for some distance by a porous ccenenchyma. 
In addition to the corals called by Dana Porites erosa, P. informis, P. monticulosa, and 
P. contigua (= P. dane M.-E. & H.), Dr. Verrill described three as new “ species.” 
All subsequent writers on the Poritids have accepted this genus, without serious alter- 
ations in the description. Dr. Klunzinger (1879),t writing from the current point of view 
that the compound stony corals were built up by the secondary fusions of their walls, 
describes the difference between Synarea and Porites—that the former are united by 
ccenenchyma, the latter directly by their walls. On this diagnosis, however, compare 
Vol. IV., p.19. He consequently placed Synarwa by itself at the end of the Poritids, that 
is, after Goniopora and Alveopora, which at that time was thought to be a Poritid. 
Martin Duncan (1884), in his attempted revision of the Milne-Edwards classification, 
repeated Dr. Klunzinger’s diagnosis, but again brought Synarea into close proximity with 
Porites. 
The present writer, in 1899, expressed doubts as to whether Synarwa showed any real 
generic distinction from Porites. The subject was followed up incidentally in a second 
paper,§ while in Vol. IV. of this Catalogue Synarea is definitely merged in Porites. 
The reasons may be summed up as follows: The distinction is not fundamental—that is, 
there is no real variation in plan as there is, for instance, between Goniopora and Porites. 
The differences are matters only of degree. The forms in which the intra-calicular skeleton 
rises up to the level of the wall have just as much right to be included in the genus as have 
those showing the other extreme, in which the calicular skeletal elements are deeply sunk, 
which is the supposed generic character of Neoporites and Stylarea. Every intervening stage 
can be seen without any real difference in the essential plan of structure. Indeed, the matter 
is put beyond dispute by the fact that in a very large number of typical Porites all the calicles 
down the sides and on the under surfaces are typical of the supposed new genus Synarea. 
* Bulletin Mus. Comp. Zool. Camb. Mass. (1864) iii. p. 42. 
{ Die Korallthiere des Rothen Meeres, ii. p. 39. 
t Journ. Linn. Soc., xviii. p. 187. § Tom. cit., xxvii. pp. 127, 487. 
Cc 
