2 I Bl ! 1 .!.TIN 76, UNITED STATES NATIONAL MUSEUM 



very sparingly in individuals which have very few: pedicellariae without enlarged 

 teeth on the moderately broad terminal lip; straight pedicellariae variable— small 

 i.. large lanceolate to broadly ovoid, or even clam-shaped, edentate to unguiculate. 



Subgenus Leptasterias Verrill 



Leptasterias mvtteri group; size small, symmetry pentamerous. North Atlantic, 

 Dorth Pacific, Antic 



Includes the following species": arctica (Murdoch), austera (Verrill), fisheri 

 Djakonov, groenlandica (Lutken), hylodes Fisher, hyperborea (Danielssen and Koren), 

 leptalea Verrill, liitoralis (Stimpson), miilleri (Sars), ochotensis (Brandt), orientalis 

 I )jakoiio\ . U in m Stimpson. 



LEl'TASTERIAS ARCTICA (Murdoch) 



Plate S, Figures 5, 5a-5h; Plate 9; Plate 10; Figures 1-4; Plate 14-16 



\eriat arctica MtjbdOCH, Report of the International Polar Expedition to Point Barrow, 

 Alaska, under Lieutenant Ray, 1SS5, p. 159. — Von HoFSTEN, Die Echinodermen des 

 Eisfjords, Ktlng. Svenska Vetenstapsakad. Hand!., vol. 54, no. 2, 1915, p. 63. 



Asterias nautarum Bell (nomen nudum), Sladen, Challenger Asteroidea 1889, p. S24 

 (nomen nudum). Sec Fisher, Ann. and Mag. Nat. Hist., ser. 9, vol. IS, 1926, p. 198. 



Asterias mulleri Lttdwig, Fauna Arctica, vol. 1, 1900, p. 482. 

 ritu hyperborea Verrill, Amer. Nat., vol. 43, 1909, p. 553. 



Leptasterias arctica Verrill, Shallow-water Starfishes, 1914, p. 120, pi. 56, figs. 1, 2; pi. 71, 

 figs. I, 2; pi. 72, fig. 1; pi. S3, figs. 2, 2a.— Clark, Rep. Can. Arct. Exp., vol. 8, part C, 

 1920, p. 9e (Dolphin and Union Strait, Northwest Terr.) 



This highly variable species is the equivalent of L. mulleri (Sars) to which it 

 is closelj relate, 1. Its status with reference to mulleri is the same as that of Asterias 

 amurensis to A. rubens. In neither case is intergradation known, although very 

 likely it occurs. L. arctica has two fairly well-marked formae. The northern or 

 typical form is much less like miilleri than the larger Bering Sea race. It has been 



ested " that /.. hyperborea (Danielssen and Koren) is a high arctic form of miilleri. 

 It is noteworthy that the arctic phase of arctica (forma artica) is not like hyperborea. 

 It /.. arctica intergrades with miilleri it does so by a series of forms which are less 

 like mullin than its own southern form, beringensis . L. arctica forma arctica stands 

 geographically between beringensis and mUUeri. 



Diagnosis. Forma arctica: Rays live; size small to medium. R = 4 to 5 + r in 

 fully grown examples, or 3.5 r in small specimens. Largest of type series, R 36 mm., 

 r 8 mm., R 4.5 r. Disk small, rays slightly swollen at base, gradually tapered to 

 a blunt extremity. Hays well arched, with curved lateral face. Spines coarse, 

 unequal in diameter abactinally, subcapitate, striate, surrounded by a wreath (often 

 prominent I of crossed pedicellariae; carina! spines more crowded than the irregularly 



ed but uncrowded dorsolaterals, usually somewhat larger, and arranged in a 

 zigzag series disting uishable in the dried state at least. Supermarginal, infero- 



,.,, '.' ', WWKMttfoll mtxicanum LU.ken {Lc,.: , , „ m , West In ,, 1!in se,rfi,he S . Bull. Stat • 



... ' ' '• n \\ 1 " lown of this form to venture an opinion. As VerrUl says, it may 



w h rc. ™a T«r aZ Ji An T. Verri "- **""**■ **«*> f^cularU Terrier 



wnicn is s Tarmilrr and LtjXatUrlat win Rathbun, i \aster 



52, tor summary, 



