NO. 1944. NEW GENERA AND SPECIES OF STARFISHES— FISHER. 631 



c'. Size small ; radial tabulate plates roundish, a few distal abactinal plates isolated 

 singly between consecutive paii's of contiguous superomarginals ; furrow 



spines 7 or 8; subambulacral spines and granules in 3 series confinis} 



C-. Size medium or large; radial tabulate plates hexagonal. 

 d}. Furrow spines 14 or 15; large radial plates with 12 to 23 central granules. 



mimieus. 



<P. Furrow spines 8 to 10; large radial plates with 2 to 4 central granules. 



bipunctus. 



a-. Superomarginals separated on outer part of ray by a single series of abactinal plates, 

 but the last few plates may be in contact medially. 

 ¥. Size small; distal marginals with a small central tubercle; marginals tumid; 



fmTow spines 4 or 5 tnainillatus. 



b-. Size large; distal marginals not tuberculate; marginals not individually tumid; 

 furrow spines 8 to 12 symbolicus. 



ROSASTER NANNUS, new species. 



A small species resembling R. conjlnis (Koehler), but differing in 

 having larger, hexagonal, radial plates, with differently formed and 

 characteristic marginal granules, fewer furrow spines (4 or 5) and 2 

 instead of 3 series of subambulacral spines and granules. Disk 

 stellato-pentagonal, the rays at first tapering abruptly to the third 

 superomarginal, which meets its fellow medially, then very gradually, 

 the extremity being blunt and the general form resembling that of 

 Paragonaster; breadth of ray at inner end of third superomarginal 

 equaling first 2 J superomarginals measured on ambitus; radial plates 

 large, with large, valve-like granules on the lateral borders, and 

 smaller ones on the transverse margms; furrow spines 4 or 5; sub- 

 ambulacral armature in 2 longitudinal series, the inner consisting of 

 3 or 4 spines; consecutive plates of median radial series joined by 2 

 internal ossicles, and joined to the adradials by 2 transverse ossicles, the 

 former being absent on the adradial series. R == 24 mm., r = 6.5 mm., 

 11 = 3.7 r; breadth of ray at mid-interbrachium, 7 mm. 



Type.— C&t. No. 30539, U.S.N.M. 



Type-locality. — Station 5152, Tawi Tawi Group, Sulu Archipelago 

 (lat. 5° 22' 55" N.; long. 120° 15' 45" E.), 34 fathoms, white sand. 



Dorigona conjinis Koehler has been included in this genus only on 

 the evidence of external characters. It appears to be related to 

 R. nannus. 



Although the specimens are small the gonads are relatively very 

 large, and fill up most of the coelom of the base of the ray. They 

 consist of thick unbranched or bifid sacs in clusters of 1 to 5, these 

 extending in a series close to the margin as far as the third supero- 

 marginals, or until the latter join medially. There seem to be at 

 least 5 of these clusters in each series. 



The rhjs are formed for the greater part of their length, above, by 

 the superomarginals, which are all longer than wide, as seen from the 



1 Dorigona confinis Koehler, An account of the shallow-water Asteroidea. Echinoderma of the Indian 

 Museum, part 6, Asteroidea (n), June, 1910, p. 67. 



