NEW STARFISHES FROM DEEP WATER OFF CALIFORNIA AND ALASKA. 299 



Family BENTHOPECTINID.-F. Verrill, 1899. 



Genus BENTHOPECTEN Verrill. 



Benthopecten Verrill, Amer. .lour. Sci., XXVIII, 1884, "Jls i /;. epino&ua Verrill). 



I'artirrliast' r SlufU-n. ill Ntirr. chalk'iim'r Exp., 1, GUI, 1885. 



Benthopecten acanthonotus, new species. 



Kays 5. R=? (tip of all of rays broken); r=9.5 mm. Breadth of ray at base, ]() mm. Length 

 of interradial spine, 12 mm. 



Kays narrow, depressed, very gradually tapering, probably very long; disk small, the abactinal sur- 

 face inflated; along rays the abaetinal surface nearly plane; lateral walls low, the rays having conse- 

 quently a thin, flat appearance; actinal surface convex. 



Abactinal surface beset with delicate, rather widely spaced, capillary spinelets, 1 to 2.5 mm. long, 

 with a rugose surface, these decreasing in number and becoming slenderer and shorter as they proceed 

 along the rays, here and there a few longer; on disk about 10 longer spinules (5 mm.), widely 

 spaced; on abactinal surface many pedicellarise, consisting of 2 opposed semicircular series of short 

 curved spinelets, or mure often the spinelets, about 12 in number, forming a circle with points meeting 

 in the center, such apparatus from 0.75 to 1.5 mm. in diameter; spinelets rather numerouson disk and 

 basal portion of rays, decreasing in numbers as they proceed outward; papulae numerous on disk 

 and extending along rays to sixth superomarginal, being confined to sides of area beyond fourth 

 superomarginal. 



.Marginal plates confined to side wall of ray, considerably longer than high; upper series apparently 

 sol somewhat obliquely as regards the long and dorso-ventral axes. Each superomarginal bearing in 

 the center a long, slender, tapering spine, that of the 3d or 4th plate being longest (8 mm.); 2 or 3 

 tiny capillary spinelets on adoral half of plate, and 1 or 2 in vicinity of spine. Each iuferomarginal also 

 bearing a long slender spine, on a slight boss, directed horizontally outward, the fourth being longest, 

 each about equal to or a shade larger than the corresponding superomarginal spine; a second spinule, 

 J to 3 the length of the larger, just below it; a few scattered capillary spinelets on the general surface; 

 between lower odd interradial, and first iuferomarginal of either ray, and between first and second 

 infcromarginals, a characteristic pedicellarian apparatus, consisting of 2 combs, each of about or 10 

 curved spinelets, meeting over the suture, the apparatus occupying the whole height of the plate 

 (3 mm.); it sometimes occurs between the second and third plates in addition, or skips the suture 

 between the first and second. On one side of one ray an apparatus occurs also between the 6th and 

 7th, and 9th and 10th plates, there being also 4 or 5 spines from an adjacent adambulacral entering 

 into the make-up. Dorsal odd interradial plate with a prominent spine, 12 mm. long; the lower with 

 a spinule, about the size of the adjacent iuferomarginal spinules. 



Adambulacral plates comparatively large, with a slight semicircular prominence into the furrow; 

 armature consisting of (1) a furrow comb of 4 or 5 slightly curved, slender, subcylindrical, blunt 

 spinelets, 3 of which are about equal, the aboral shorter, and when there are 5 the adoral also, these 

 spinelets placed close together, and a wide interval between successive scries, the spinelets usually 

 standing vertically; (2) on the actinal surface 2 slender, slightly tapering, blunt spinules in a transverse 

 series, the inner J the length of the outer, which about equals 2 plates in length (3 mm. near base of 

 ray) ; these spinules are articulated to slight knobs or bosses. 



Mouth plates large, convex actinally, and the united pair with a broad furrow margin; in contour 

 the combined pair broadly hatched-shaped; armature consisting of (1) a furrow series of 4 spines, 

 which increase rapidly in size toward inner angle, where the innermost of 2 companion plates forms 

 2 prominent teeth, much heavier than the others; (2) on actinal surface 5 spines and spinelets, 

 forming a linear series to outer end of plate, decreasing in size as they proceed outward, the inner 

 spines being stout, cylindrical, and slightly tapering, the outermost slender and much shorter, the 

 intermediate 3 graduated between the extremes. 



Actinal interradial areas very small, second adambulacral plate in contact, with the first infero- 

 marginal; 2, or at most 3, intermediate plates. A comb of 3 to 7 curved spinelets meets a similar but 

 smaller comb on the inferior interradial marginal plate, forming one of the peculiar pedicellarian 

 apparatuses. On one interradius this is represented by an upright spinule and a rudimentary comb 

 which is turned toward the interradial line. 



