214 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.46. 



R = 41 mm., r = 8.5 mm., R = 4.8 r; breadth of ray at base, 9.5 mm. 

 Rays slender, evenly tapering, abactinally plane; disk slightly convex; 

 marginal plates very regular, mostly longer than wide, regularly 

 decreasing in size, not alternate large and small; abactinal plates 

 roundish or hexagonal, sometimes with faint indication of lobing, 

 arranged in quincunx in regular longitudinal series; actinal plates in 

 3 regular series at base of ray; adambulacrals with proximally 3 

 rather narrow furrow spines, 2 distally; 2 subambulacral spines and 1 

 to 3 subambulacral pedicellarise. Granules of abactinal surface 

 polygonal, close-set, fairly uniform, not larger in center of plate, 

 about 8 to 10 in the transverse diameter of a carinal plate. Granules 

 surrounding papular pores unequal, some of them a little larger than 

 the granules of plates. Papulee single, at the corners of the plates. 

 Superomarginal plates 18, encroaching conspicuously upon abactinal 

 surface. Inferomarginals 20. Actinal granules increasing in size 

 toward furrow. On proximal half of ray there are rather abundant, 

 granuHform 2- or 3-jawed pedicellarise, from 2 to 5 times the diameter 

 of adjacent granules. 



Type.~Cat. No. 32637, U.S.N.M. 



Type-locality. — Station 5146, vicinity of Siasi, Tapul Group, Sulu 

 Archipelago, 24 fathoms, coral sand, shells. 



FROMIA HEMIOPLA, new species. 



Differing from F. armata Koehler in the absence of abactmal conical 

 tubercles, and the slighter development of the margmal tubercles; 

 differmg from F. milleporella m having 1 or more tubercular granules 

 in the center of the marginal plates of the distal three-fourths or half 

 of ray, in having slenderer rays, and broad, but thin, spatulate fur- 

 row spines. R = 36 mm., r = 9 mm., R = 4 r; breadth of ray at base, 

 10 mm. 



Margmal plates convex, the granules increasing m size toward the 

 center, where the plates of at least the distal half of ray bear 1, 2, or 

 even more enlarged tubercular granules, there bemg as high as 5 to 

 10 on the distal marginals of the type. The first half dozen plates 

 usually lack a tubercle, and the tubercles become a trifle more pronii- 

 nent as the end of the ray is approached. Superomarginals 19 or 20; 

 mferomarginals about 23 or 24. Adambulacral plates with proxi- 

 mally 3 or 4, or near end of ray 2, broad, flat subtruncate (spatulate) 

 furrow spines, the end of the series with a curved contour and part or 

 all of the aboral spine usually underlying the adoral spine of the 

 succeeding plate. Subambulacral spines 2, sometimes 3, consider- 

 ably shorter, round-tipped, heavier, but not broader than the furrow 

 spines, and forming a straight series. External to these are 2 or 3 

 granules larger than the succeeding. Part or all of a second series of 

 smaller granules belongs to the adambulacral plates. 

 Type.— Cat. No. 32638, U.S.N.M. 



