SHALLOW-WATER STARFISHES 



253 



SOLASTER DAWSONI ARCTICA Verrill, subsp. nov. 

 Plate LXXXVII, figures 6, 6a (details) ; text-figure No. 14. 



This subspecies is very similar in general appearance to 5". endeca 

 and S. dawsoni. Its dorsal pseudopaxillae are rather larger than in 

 the former and are flat-topped. The larger dorsal ones, on the disk 

 and bases of the rays, are covered with twenty to thirty, or more, 

 small, short, very slender, thorny spinules, of which about fifteen to 

 twenty-five are marginal, the rest central; all are short, rising to 

 about the same height, but the central ones may be a little shorter, 

 in some cases. Papulae are small and stand singly. 



The adambulacral plates bear two rather long and slender, nearly 

 equal, furrow-spines, sometimes with a smaller supplementary one, 



FIG. 14. 



Solaster dawsoni arctica Ver., type, Arctic O. U. S. Nat. Mus. Two adambulacral 

 plates and their spines; a, a, outer or actinal combs; b, b', inner or furrow groups. X 17. 



and a transverse comb of about five or six somewhat shorter and 

 stouter spines, not very diverse in length, so that their tips lie in a 

 slightly convex line. The furrow-spines rise to about the same 

 height. 



The inferomarginals are relatively rather large and prominent, 

 strongly compressed, transversely oblong, covered with a great num- 

 ber of minute, rough spinules, in three or four transverse rows. The 

 superomarginals are small, but distinct, not half as large as the lower 

 ones, but twice as large as the dorso-laterals, spinulated like the 

 lower ones. 



Peractinals are small and inconspicuous, except proximally. The 

 oral plates have about six or seven graded spines on each end, besides 



