608 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 43. 



CTENOPLEURA, new genus. 



Allied to Astropecten, but differing in having the gonads in a 

 crowded series parallel to the marginal plates, and extending about a 

 third the length of ray; inferomarginal plates with a lateral, oblique, 

 compact comb of 3 to 5, usually 4, slender appressed spines, closely 

 resembling the lateral comb of PersepTionaster, and in addition 1 to 5 

 flattened, appressed spines on the actinal surface; adambulacral 

 plates with usually 4 or 5 furrow spines (or, on the second and third 

 plates, sometimes 6 or 7) instead of 3, the usual number in Astropecten; 

 subambulacral spines small, none enlarged; often a fasciculate sub- 

 ambulacral pedicellaria is present; Polian vesicles 5. Other char- 

 acters as in Astropecten. 



Type oftTie genus. — Ctenopleura astropectinides, new species. 



This genus includes also Astropecten ludwigi de Loriol, of Japan, in 

 which the gonads are arranged in series extending about a third the 

 length of the ray. In Astropecten the gonads form a single tuft on 

 either side of the interbrachial septum. The arrangement of the 

 gonads in series will separate Ctenopleura from Lepty chaster, Bathy- 

 hiaster, Psilaster, BlaMaster, Astromesites, Ctenophoraster, PersepTio- 

 naster, Tritonaster, and Patagiaster, while the ver}'' restricted develop- 

 ment of the actinal intermediate plates will distinguish it from other 

 AstropectinidsB having serially arranged gonads, such as AntJiosticte, 

 Tethyaster, ThrissacantMas, Dipsacaster, and Plutonaster. The arma- 

 ture of the marginals will separate Ctenopleura from Lonchotaster and 

 Ripaster in which the gonads are not described. 



CTENOPLEURA ASTROPECTINIDES, new species. 



Related to C. ludwigi (de Loriol)^ but differing in having longer, 

 narrower rays, shorter, stouter superomarginal spines confined to 

 marginal angle of ray, strongly 4-lobed abactinal plates on papular 

 areas, and fewer actinal inferomarguial spines. E = 129 mm., r=25 

 mm., E, = 5r; breadth of ray at base, 28 mm. Disk small, rays long, 

 narrow, very gradually tapering to a bluntly pointed extremity; 

 abactinal integument thin, paxillsB tall, spaced, bearing a compact 

 upright group of 10 to 15 subequal, terete, slender, blunt spinelets 

 varying from slightly shorter to slightly longer than the cylindrical, 

 barrel-shaped, or compressed pedicels; superomarginals encroaching 

 conspicuously upon abactinal area, the dorsal face tumid and about 

 twice as wide as the lateral; marginal area of plates covered wdth 

 short, slender, crowded spinelets, becoming coarse roundish granules 

 on the summit of median transverse tumidity, the angle between 

 lateral and dorsal facets bearing a transverse series of 2 to 4 short 



^Astropecten ludwigi de Loriol, M6m. soe. phys. et d'hist. nat. Genfeve, vol. 33, pt. 2, No. 1, 1899, p. 21, 

 pi. 2, fig. 4. (Tago, Japan.) 



