90 Proceedings of the Biological Society of Washington. 

 Cheiraster diomedeae, new species. 



Diagnosis. —Rays 5, long, slender, with narrow marginals carrying 1 

 superomarginal and usually 2 inferomarginal spines; abactinal plates 

 with 10 to 15 spinelets on disk, and on ray usually 2 to 7 ; enlarged cen- 

 tral spinules scattered on outer half or two-thirds of ray ; adambulacral 

 furrow spines 10 to 12; 1 subambulacral spine except on outer part of 

 ray, where there are 2; 11 to 13 oral, and 1 prominent suboral spine. 

 Papularia small, with about 25 pores, which do not reach farther than 

 opposite middle of third superomarginal. Pectinate pedicellariae on the 

 abactinal surface, between the proximal superomarginals, over the inter- 

 marginal suture, on the actinal intermediate plates; fasciculate pedicella- 

 riae on the actinal surface of inferomarginals. Related to Ch. snyderi 

 Fisher. R=86 mm., r=10mm., R=8.6r; breadth of ray at base (be- 

 tween first and second superomarginals, 10 mm. ; at middle of ray, 5 mm. ). 



Type.— C&t. No. 37,035, U. S. N. M. 



Type locality. — "Albatross" station 5512, Iligan Bay, north coast of 

 Mindanao, 423 fathoms, gray mud, fine sand; bottom temperature 

 52.8° Fahr. 



Lithosoma penichra, new species. 



Diagnosis. — Differing from L. actinometra Fisher in having slenderer, 

 longer rays, narrower marginal plates, restricted petaloid papular areas, 

 and more angular furrow margin to the adambulacral plates, the consecu- 

 tive pairs of tube-feet being separated, beyond base of furrow, as in 

 Nymphaster; surface of plates and encircling granules as in L. actino- 

 metra ; width of ray at proximal end of first pair of superomarginals 

 (fifth) which meet medially equal to length of 3 or 3% superomarginals 

 measured on ambitus (5 in L. actinometra). R=86 mm., r=21mm., 

 R=4+ r; breadth of ray at interradius 24 mm., at proximal end of fifth 

 superomarginal, 9.5 mm. 



Type locality. — "Albatross" station 5528, between Siquijor and Bohol 

 Islands, Philippines, 439 fathoms, globigernia ooze, bottom temperature 

 53.3° Fahr. 



Nardoa tumulosa, new species. 



Diagnosis. — In a general way resembling N. frianti Koehler in having 

 prominent, large, hemispherical abactinal plates, but these much fewer 

 and relatively slightly larger than in frianti, lower in proportion to width 

 and evenly rounded or dome-shaped. They are confined to the abactinal 

 surface and proximal two-thirds of ray; plates of distal third of ray 

 small, crowded, convex ; disk high. R=about 90 mm., r=about 14 mm., 

 R=6.4 r; breadth of ray at base, 17 mm. ; height of disk, 21 mm. 



Type.— Cat. No. 37,028, U. S. N. M. 



Type locality.— "Albatross" station 5160, off Tinakta Island, Tawi 

 Tawi Group, Sulu Archipelago, 12 fathoms, sand. 



