THE STONY CORALS OF THE PORTO RICAN WATERS. 
3oy 
Family AGARIC! Verrill. 
Genus SIDERASTREA de Blainville, 1830. 
The synonymy o£ this genus is fully considered in my Eocene and Lower Oligocene Corals of the 
United States.’ 
Siderastrea radians (Pallas). PI. xv; pi. xvi, fig. 2. 
1766. Madrepora radians, Pallas, Elench. Zooph., pp. 322-323. 
1767. Madrepora astroites, Linnteus, Syst. Nat., ed. xii, p. 1276, non Pallas, 1766. 
1786. Madrepora galaxea, Ellis & Solander, Nat. Hist. Zooph., p. 168, pi. xlviii, tig. 7. 
1801. Astrea galaxea, Lamarck, Syst. Anim. s. Vert,, p. 371. 
1815. Astraea radians seu astroites, Oken, Lehrb. Naturgesch., Bd. 1, p. 65. 
1830. Astrea ( Siderastrea ) galaxea, de Blainville, Diet. Sci. Nat., t. lx, p. 335. 
1834. Astrx a astroites, Ehrenberg, Cor. Roth. Meer., Abhandl. K’gl. Akad. Wiss. Berlin for 1832, p. 319. Non Explanaria 
galaxea Ehrenberg = Cyphastrxa savignyi Milne-Ed wards & Haime. 
1846. Siderina galaxea, Dana, Zooph. Wilkes Expl. Exped., p. 218, pi. x, figs. 12, 126, 12c (non figs. 12a, 12d). 
1880. Siderastrxa galaxea, Pourtales, Mem. Mus. Comp. Zool., vol. vn, pt. 1, pi. xi, figs. 14-21, pi. xv, figs. 1-12. 
1895. Astrxa radians, Gregory, Quart. Jour. Geol. Soc. Lond., vol LI, p. 277. 
Linnseus described a Madrepora astroites in Systema Naturae, ed. x, p. 796, but the description is 
not sufficient for even approximate identification. The only reference in the synonymy that I have 
been able to verify is the one to Sloane’s Jamaica (vol. i, p. 54, pi. xxi, Lapis astroites s. stellaris). I can 
not identify this figure. When Pallas’s description of M. radians is taken together with Seba’s figures 
(pi. cxii, figs. 12, 14, 17, 18), one can be reasonably sure of the identification being correct. The 
Madrepora astroites of the twelfth edition of Linnaeus is the same as the M. radians of Pallas. It 
apjiears to me that astroites of Linnaeus must be dropped altogether, and that radians of Pallas must be 
adopted. 
There is one excellent specimen of this species in the collection from Mayaguez. It is an 
explanate mass, subquadrangular in horizontal outline; the greatest distance across is about 11 cm., 
lesser about 10 cm., and about 2 cm. thick. 
Siderastrea siderea (Ellis & Solander). PI. xiv, fig. 1, 2; pi. xvi, fig. 1. 
1786. Madrepora siderea, Ellis & Solander, Nat. Hist. Zooph., p. 168, pi. xlix, fig. 2. 
1816. Astrea siderea, Lamarck, Hist. Nat. Anim. s. Vert., t. ii, p. 267. 
1830. Astrea ( Siderastrea ) siderea, de Blainville, Diet. Sci. Nat., t. lx, p. 335. 
1834. Astrxa tricophylla, Ehrenberg, Cor. Roth. Meer., Abhandl. K’gl. Akad. Wiss. Berlin for 1832, p. 319 (fide Milne- 
Ed wards & Haime). 
1846. Pavonia siderea, Dana, Zooph. Wilkes Expl. Exped., p. 331. 
1850. Siderastrea siderea, Milne-Ed wards & Haime, Ann. Sci. Nat.., 3ieme s6r., Zool., t. xn, p. 141. 
1857. Astrxa siderea, Milne-Edwards & Haime, Hist. Nat. Corall., t. ii, p. 509, pi. D7, fig. 2. 
1863. Siderastrxa cremdata var. antillarum Duncan, Quart, Jour. Geol. Soe. London, vol. xix, p. 435. 
1863. Siderastrxa grandis, Duncan, op. sup. cit., p. 441, pi. xvi, figs. 5a, 5b. 
1871. Siderastrxa siderea, PourtalSs, 111. Cat. Mus. Comp. Zool., No. iv, p. 81. 
1895. Astrxa siderea, Gregory, Quart. Jour. Geol. Soe. London, vol. Li, p. 278. 
Gregory places Siderastrea globosa Milne-Edwards & Haime doubtfully in the synonymy of this 
species. From the original description of the species I would judge that it is not a synonym of 
S. siderea. Siderastrxa slellata of Verrill, from Brazil, is a distinct species, and does not belong in the 
synonymy of S. siderea. It usually possesses four complete cycles of septa, but in most of its characters 
it resembles S. radians more closely. The upper portions of the septa are flattened, as in the latter 
species. The calices may form short series, sometimes are even meandriform. The examination of 
a large suite in the U. S. National Museum leads me to the conclusion that it is a valid species. 
There are two splendid specimens of S. siderea in the Porto Rican collection. The larger is a head, 
possessing a greater diameter of about 20 cm., a lesser of about 14 cm., and a height of 15+ cm. The 
specimen grew over the surface of a mass of the same species and the thickness of this mass is included 
in the measurement of the thickness of the specimen. 
Usually the leading distinction between Siderastrxa radians and Siderastrxa siderea is considered 
to be that the latter possesses four complete cycles of septa, whereas the former has the fourth cycle 
1 Mon. U. S. Geol. Sur., No. xxxix, 1900, p. 154. See also “Some fossil corals from the elevated reefs of Curayao, 1 etc. 
Samml. des Geolog. Reichs. Mus., Leiden, ser. ii, Bd, it. Heft 1, Leiden, 1901, pp. 60, 61. 
