238 BULLETIN 16, UNITED STATES NATIONAL MUSEUM. 



Madroporic bod}' ver}' convex with irregular stria; and situated, as a rule, 

 about its own diameter distant from margin. Measurements of type: R=175 

 mm.; r=15 mm.; R=11.6 r. Breadth of ray at base 19 mm. 



Variations. — Tlic principal variations have already been stated in the fore- 

 foino' description. These are so strikmg in certain particulars that it has been 

 dillicult to decide whether the specimens belong to one or two species. In the 

 type the papula? extend along the ray as far as the thirteenth to sixteenth super- 

 omarginal plates, wliile in two specimens from station 3330 they reach as far as the 

 twentv-third, in one other to the eighteentli and in another to the fourteenth, forming 

 a pretty regular transition. In a small specimen from station 4238 the papulie reach 

 to the eightii sui)cromarginal, and in a full grown example (no locality) as far as the 

 ninth to twelfth plate. In the large examples, therefore, the variation is between 

 nine and twenty-three, the type being between the two extremes. The specimens 

 from station 3330 are otherwise aberrant in having usually only four, or tliree and 

 four (but in one case five), furrow spinules proximally, and one specimen has only 

 one subambulacral spine distally. This last example has two to six inferomarginal 

 pedicellariae proximally, and rather more than the normal number abactinally. 

 The two varieties intergrade so perfectly and the differences in spinulation alluded 

 to are so inconstant that I have regarded the specimens as belonging to a single 

 species. 



Type.— Cat. No. 27800, U.S.N.M. 



Type-locality. — Albatross station 3331, north of Unalaska, 350 fathoms, mud. 



Distribution. — Southern Bering Sea to southeastern Alaska, 108 to 351 fathoms; 

 in shallower water than A^. aciculosus. 



Specimens examined. — Ten; Albatross station 3330, same as type-locality, 351 

 fathoms, black sand, mud, four specimens, U.S.N.M. ; station 3331, type-locality, 350 

 fathoms, one specimen, IT.S.N.M. ; station 3608, Bering Sea between Unalaska and 

 St. George Island, 276 fathoms, gray sand, U.S.N.M. one specimen; one specimen 

 without locality, probably Bering Sea, U.S.N.M.; station 4230, vicinity of Naha 

 Bay, .Vlaska, 240 to 108 fathoms, rocky, one specimen, Albatross, 1903; station 4238, 

 vicinity of Yes Bay, 229 to 231 fathoms, mud, rocky, two specimens, Albatross, 1903. 



Remarks. — The specimens ranged imder this species differ from aciculosus in 

 having much less conspicuous abactinal accessory or auxiliary spinules and a papu- 

 lar area of variable extent on the rays. The absence of long accessory abactinal 

 spinules gives variabilis a very different facies from the preceding form. 



From pedicellaris, which I fu-st believed to be a subspecies, variabilis differs 

 in lacking the numerous inferomarginal and "abactinal pedicellarife, and in the 

 variable and less extensive papular areas. The disk of pedicellaris is larger and the 

 accessory spinules mofe numerous and longer, giving the abactinal surface an 

 appearance only slightly less bristling than that of aciculosus. 



NEARCHASTER PEDICELLARIS (Fisher). 

 PI. 23, fig. 4; pi. 25, fig. 1; pi. 27, fig. 3; pi. 118, fig. 2. 

 AcantharchaalcT variabilis pedicel hir is, Fisher, Zool. Anz., vol. 35, March 29, 1910, p. 550. 

 Diagnosis. —RescmhVmg A. vaiiahilis but differing in having a large number 

 of abactinal pectinate pedicellaria^. which arc scattered all along ray; in the pres- 

 ence of numerous inferomarginal and usually one or two actinal interradial pedi- 



