THE STONY CORALS OK THE PORTO RICAN WATERS. 
HI 5 
Madrepora porites cites this same reference to Seba. I have, therefore, seized upon the “ Cor allium, 
poris stellatis” of Seba as the type of Porites porites (Pallas). Seba states that the coral is found on the 
shores of Curasao. 
I have recognized only one species of branching Porites in the West Indian region, considering 
all specimens that show intergradation as belonging to the same species. Practically the same con- 
clusion was reached by Rathbun. 1 Pourtales states ‘ 1 Porites clavaria an 1 furcata are * * * rather 
difficult to distinguish by any constant characters derived from the caliele, as they vary considerably 
in the same specimen.” 2 3 Gregory (op. et loc. sup. cit. ) has combined what were divided 'nto two 
species. I find the treatment accorded the species by Rathbun excellent, and invite especial attention 
to what he has written (sup. cit.). The variation of this species is enormous. By taking individual 
colonies or isolated specimens from separate localities, the number of “species” could be multiplied 
indefinitely. PI. xxix, and pi. ii, tig. 4, represent almost the extremes. A considerable number of 
fairly well characterized varieties may be recognized. I have accordingly divided the specimens from 
Porto Rico into three “fo’rmse,” and have illustrated each of them. 
When I employ the specific designation Porites porites (Pallas) without placing the name of a 
forma or variety after, it will apply to any of the branching Porites from the West Indian region with 
the special septal arrangement later described. Usually, however, the particular forma of the species 
will be indicated. 
I had hoped to find in the U. S. National' Museum a specimen of Porites from Curasao that would 
be practically a duplicate of the specimen figured by Seba, but could find none, though there are some 
from Florida. We have from Curacao a specimen that agrees fairly well with Seba’s figures, except 
the branches are more crowded. It is represented on pi. xxviii bv illustrations from photographs. 
It can scarcely be referred to any one of the three formse recognized in the Porto Rican collection, but 
resembles furcata more closely than it does clavaria. The calicular structure is more pronouncedly of 
the furcata type. There are either five or six pali, but without taking a precise census five seems to 
be the more common number. Six is the usual number on the lower portion of the living part of the 
corallum, while five is the usual number on the ends of the branches. The calices are superficial 
except near and on the ends of the branches, where they are fairly deep. Twelve seems to be the 
constant number of septa. The calices show a bilateral symmetry. At one end- of the plane of sym- 
metry is a free septum joining directly the “columellar tangle”; 8 at the other is a septum with a 
septum on each side of it and bending toward it. There are four other septa on each side of the plane 
of symmetry. They are fused together and to “the columella tangle” in pairs. This arrangement is 
not constant. In one calice there are two groups of three septa each and three groups of two septa 
each, without apparent bilateral symmetry, but this arrangement can be easily derived from the usual 
condition by the solitary directive septum joining to an adjacent pair of septa. This would make the 
asymmetry apparent but not real. There is a palus before each group of septa, and often there is 
also a palus before the solitary directive. The columella shows three conditions — the columellar axis 
,may be open, there may be a spongy columella, or the columella may be terminated above by a 
tubercle. The wall is wide and flattish on the older portions of the colony and thin and acute on the 
younger portions on the ends of the branches. The usual diameter of the calices is 1.5 to 2 mm. 
This specimen has been described in considerable detail, because it may be regarded as something 
like a type of the species — it is a topotype. 
The calicular structure of this Curagaoan specimen and that of the three formse subsequently 
recognized show the same range in variation, i. e., number and arrangement of septa, characteristics 
of pali, and character of columella. Usually forma clavaria has the columella terminated above by a 
tubercle, but not always; in forma furcata there may or may not be a columellar tubercle; the same is 
true of forma divaricata. These notes on variation are based not upon comparing different specimens 
but upon comparing the calices of the same specimen. 
The description of the calicular structure will not be repeated in discussing the formae. 4 * * * 
’Cat. Politicise, Proc. U. S. Nat. Mus.,vol. x, 1887, pp. 356-357. 
-Til. Cat. Mus. Comp. Zool., No. iv, 1871, p.85. 
3 This expression is borrowed from Bernard. 
4 Two interesting papers on the arrangement and development of septa in Porites should be cited: H. M. Bernard, 
“On the Structure of Porites, with Preliminary Notes on the Soft Parts,” Journ. Linn. Soc. Lond.. vol. xxvii, 1900, pp. 
487-503, pi. 35 (fig. 5, p. 492, gives a diagram that applies to the septal arrangement of Porites porites ) : J. E. Duerden, “Order 
of Appearance of the Mesenteries and Septa in Madreporaria,” Johns Hopkins Univ. Lire., vol. xix, No. 146, June, 1900, 
pp. 47-53. 
