ASTEROIDEA OP NORTH PACIFIC AND ADJACENT WATERS — FISHER 59 



Koehler, 1920 (p. 109), gives a list of the nominal forms of Pedicellaster: 



antarcticus Ludwig. parvulus Perrier. 



atratus Alcock. pourtalesii Perrier. 



formatus Koehler. reticulatus H. L. Clark. 



hypernotius Sladen. sarsi Studer. 



hyperoncus Clark (Amplteraster). scaber Smith. 



improvisus Ludwig {Hydrasterias). sexradiatus Perrier (Hydrasterias). 



octoradiatus Studer. typicus Sars. 



palaeocrystaUus D uncan and Sladen. 



Of these antarcticus, formatus, possibly hypernotius, pourtalesii, and typicus (includ- 

 ing palaeocrystaUus) are true Pedicellaster. I have examined specimens of P. pour- 

 talesii, loaned by Dr. H. L. Clark. They are too small to show the characteristic 

 actinal structure, but the larger pedicellariae are of the characteristic fanged type. 

 Atratus is possibly a true Pedicellaster. Alcock mentions large pedicellariae which is 

 a characteristic of Pedicellaster as contrasted with Anteliaster or Hydrasterias. He 

 also says that there are 14 longitudinal rows of plates (probably either 13 or 15) which 

 seems to indicate about three series of actinals. P. octoradiatus Studer is probably 

 not a Pedicellaster. P. parvulus is a young Sclerasterias, judging by one of Perrier's 

 specimens which I have examined. 



PEDICELLASTER MAGISTER Fisher 



Plate 16, Figure 3; Plate 26, Figures 2, 2a-2/; Plate 27, Figures 2, 2a-2d; 6, 6a, 66; Plate 28, 

 Figures 1, la-16; Plate 33; Plate 34, Figure 1; Plate 36, Figure 2 



Pedicellaster magister Fisher, Ann. and Mag. Nat. Hist., ser. 9, vol. 12, 1923, p. 251. 



Diagnosis. — Differing from typicus in regularly attaining a relatively gigantic 

 size, with extensive dorsolateral region and a conspicuous actinal area crossed by 

 transverse series of imbricating, four-lobed plates which increase in number for each 

 series toward the middlo third of the ray, and decrease slowly in the final third; in 

 having differently formed, slenderer-jawed, major crossed pedicellariae, as well as 

 differently shaped minor ones. Type, R 85 mm.; r 12 mm.; R = 7 r; breadth of 

 ray at base, 13 mm. Paratype, station 4792, R 70 mm.; r 11 mm.; R = 6.4 r. 

 Breadth of ray at base, 14 mm. Rays slender, flexible, slightly inflated above base, 

 very gradually tapered to a bluntly pointed extremity. 



Description. — The following description applies particularly to the full-grown 

 large specimens from stations 3223, 3224, 3257, 3258, 3675, 4786, 4791, 4792: In 

 alcoholic specimens the rays are flexible and the body wall rather thin. The arrange- 

 ment of the plates is not at all visible, since the entire surface is thickly covered with 

 small uniform spinelets 0.5 to 0.6 mm. long, their true size augmented somewhat by 

 a pulpy sheath. Between the spinelets are numerous pedicellariae, shorter than the 

 spinelets, appearing as smaller pulpy papillae, while interspersed among these are 

 the papulae — numerous in the aggregate, but only a few to each area. No spinelets 

 are conspicuous by superior size until the double row along the furrow margin is 

 reached. Along the sides and actinal surface of the ray the larger of the two sorts of 

 pedicellariae are very numerous, so closely placed as to touch one another by the 

 investing sheaths. 



