138 BULLETIN 76, UNITED STATES NATIONAL MUSEUM 



Genus STENASTERIAS VerrM 



Slcnasterias Verrill, Shallow-water Starfishes, 1914, p. 145.— Typo, Astoria* macropora 

 \ errill Fisher, Ann. Mag. Nat. Hist., ser. 9, vol. 12, 1923, p. 598. 



Diagnosis. — Rays six, slender. Differing from Leptasterias in having unusually 

 large triangular ambulacral pores separated by thin plates. Skeleton very compact, 

 the plates closely imbricated, in longiseries, with very small intervals; marginal 

 plates wide; actinals small, a short second series present; plates closely covered with 

 clusters of minute spinules; adambulacrals diplacanthid; reproduction unknown. 



Remarks. — I have not seen a specimen of this small sea star. VerrilPs types 

 have disappeared. It is probable that his specimens were all young. The following 

 account is rearranged from the original description. 



STENASTERIAS MACROPORA (Verrill) 



Aslerias (Leptasterias) macropora Verrill, Amer. Journ. Sci., vol. 28, 1909, p. 65, fig. 10, 



p. 64. (Rays said to be five!) 

 Stenasterias macropora Verrill, Shallow-water Starfishes, 1914, p. 145, pi. 50, fig. 7; pi. 74 

 fig. 4; pi. 84, figs. 5-5 i. 



Description. — Disk small; rays six, slender constricted at base, convex, with 

 median row of more prominent ossicles. R 15 mm., r 3 mm., R 5 r. Ambulacral 

 furrow unusually wide and open; tube feet and pores unusually large, the pores tri- 

 angular, overlapping by their acute angles and separated only by thin plates. 



Abactinal plates rather closely imbricated, the spaces between being very few 

 and small, with only one or two papulae; carinal plates thicker and larger, subtri- 

 angular, with acute cusps and concave edges. These overlap the plates proximal to 

 them. Dorsolaterals in three longiseries, proximally, then two, subquadrate and 

 subtriangular in outline. (Verrill, 1914, pi. 84, fig. 5h.) Dorsal spinelets numerous, 

 small, short, stumpy, usually truncate or slightly clavate, but not much enlarged at 

 tip and not much longer than thick; in small groups on the larger plates, isolated 

 on the smaller ones. 



Inferomarginal plates 25 rhombic, imbricated, overlapping the outer actinals, 

 bearing usually two or three small tapered spines, like the actinals; two series of 

 very small actinal papular spaces. 



A single row of somewhat quadrate, overlapping, actinal plates which bear one 

 or two small, rather stout, tapered spines; a series of small oblong connective ossicles 

 between these and the adambulacral plates, on the basal part of ray, each of which 

 may also bear a spine. 



Adambulacral plates strong, unusually thick radially, mostly diplacanthid; 

 spinelets long, slender, tapered, acute or subacute, carry a few small compressed 

 lanceolate straight pedicellariae. 



Straight pedicellariae compressed, acute, lanceolate, of rather large size but few 

 in number are present in actinal interradial region, and similar smaller ones along 

 the edges of the ambulacral grooves. Crossed pedicellariae "few and minute." 



"The specimens of this species are small and poorly preserved, having lost many 

 of their spines. It appears to be allied to L. aequalis more nearly than to other 



" The description Is confused. The author says that the marginal plates neit to the " peractinals" (hence the inferomarginal 

 series) runs along the under side of the rays, but "cunts upward to tht dorsal sidt at the disk." This is most unusual behavior for 

 Inferomarginal plates and if true is peculiar to Stcnasttrias. I suspect however that superomarginals were confused with infero- 

 marginals at base of ray. 



