346 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



below the ventral surface of the superomarginals forms a narrow 

 border outside the inferomarginals. The presence of a more or less 

 pulpy membrane covering the granular investment suggests an alli- 

 ance of this form with Anthenoides. An important difference is the 

 fact that in Anthenoides and Stellaster the membrane covers the 

 animal without reference to the underlying plates, while in AteloHas 

 each plate is distinct, the membrane not overlying the sutures. 



Family OREASTERIDAE Fisher. 



Oreasteridae Fisher, 1911d, p. 18 {—Pcntaccrotidae, untenable). 



Genus OREASTER Miiller and Troschel, 



Oreaster Muixek and Teoschel, 1842, p. 44. 



Pentaccros Schulze, Betrachtuug tier versteinerten Seesterne u. ihrev 

 Theile, 1760, p. 50 (not binonaial). Many authors. 



KEY TO SPECIES HEREIN RECORDED. 



a\ No marginal spines or tubercles ; a radial series of very large acorn-shaped 

 tubercles, the primary radial the largest; tubercles with flat, polygonal, 

 granules larger than the other abactinal granules, and usually with a 

 subglobose or conical, bare, knob at summit. In addition to radial 

 tubercles, others are sometimes present interradially nodosus, p. 346. 



".^ Prominent distal superomarginal and inferomarginal spines, and usually a 

 few small inferomarginal spines in interbrachia ; abactinal spines very 

 prominent, conical, heavy, and granular (the granules not larger than 

 others), with a prominent bare conical sharp tip; these spines are 

 slenderer and higher (as a rule) than those of nodosus and occur radially, 

 interradially, and usually within apical area alveolatus, p. 348. 



OREASTER NODOSUS (Linnaeus). 



Plate 102, fig. 2. 



Afiterias nodosa Linnaeus, Syst. Nat, ed. IT.IS. p. 661. 



Oreaster nodosus Bell, 1884, p. 70.— Clark, 1908, p. 280. 



Pentaccros turritiis Perbier, 1875, p. 240 (which see for earlier synonymy. 



Figured by Gray, 1866, pis. 9 and 10, under names Pentaccros modestus 



and P. iranklinii) . 



Notes on Philijrpine specimens. — The specimens vary considerably 



in the number and form of the large acorn-shaped tubercles of the 



carina! ridge, as already recorded by Clark.^ In most cases the 



tubercles are higher than the breadth at base and are capped by a 



blunt or pointed tip free from granules. Seven specimens have the 



tubercle in the center of disk. The maximum number of tubercles 



is present in specimens from station 5254, where there are .(50 in a 



typical specimen and 69 in another, having in addition to the above 



69 dorsal tubercles about 28 smaller superomarginal ones. The 



tubercle is not always terminated by a blunt or short spine, which 



is lacking in most of the Pangasinan Island examples. In these the 



1 See Clark, 1008, p. 2S0, foi- variations of specimens from New Guinea. 



