288 



BULLETIN 7G. UNITED STATES NATION.VL MUSEUM. 



Alaskan specimens. — The specimens which present the extremes of difTerence 

 from lemuscula are from off the Aleutian Islands and Commander Islands. These 

 and other typical examples of the race differ among themselves in the size of the abac- 

 tinal plates (as shown by the four photoficraphs on jtlate 72) and in the thickness of 

 the rays, as well as in the extent of the intermarginal plating. The slenderer-armed 

 examples usually have very few intermarginal plates on the rays (only a small 

 triangle in the interbrachial region) while the stouter-rayed specimens have one 

 or two series extending half the length of ray between infero- and superomarginals. 

 The presence of intermarginals is not strictly correlated with thickness of ray, for a 

 specimen \vitli moderately slender rays has the intermarginals well developed 

 (station 4777). Specimens with smaller abactinal plates have finer spinelets. 



A well-marked variety occurs at Kadiak Island (Karluk), Herendeen Bay 

 and Port Clarence, Alaska. This has rather thick rays (R = 4 to 4.5 r) more or less 

 swollen at the base, and one or two series of intermarginal plates extending a varying 

 distance along ray. The spinelets are shorter than in typical forms, and the 

 adambulacral spinelets are fewer (about twenty). There are usually two spinelets 

 deep in the furrow, on the outer part of ray. This variety passes into specimens 

 which are difficult to separate from extremes of variety B of leviuscula. They 

 may be told usually by the presence of two furrow spinelets near the end of ray 

 and by the actinal intermediate plates not reaching the end of ray. I regard them 

 as intergrades, either by extremes of individual variation or by hybridization. 

 Of course occurring as these intennediates do, all at a single station, the case is 

 different from the intergradation of terrestrial subspecies. 



Type.— Cat. No. 27779, U.S.N.M. 



Type-locality. — Albatross station 4779, near Semisopochnoi Island, Aleutians, 

 54 fathoms, broken shells, pebbles, sand. 



Distribution. — From Oregon to Bering Sea, Bering Strait, the Aleutians, and 

 south to Simushir, Kuril Islands, on the Asiatic side; typical form in moderate 

 depths, a variety more or less intermediate with leviuscula occurring at low tide at 

 Kadiak, the iVleutians, and northward. Bathymetrical range to 238 fathoms. 



Specimens examined. — One hundred and seven from the folloAvang localities: 

 Specimens of Henricia leviuscula multispina examined. 



Nature of bottom. 



2»12. 

 2849 a 

 2857. 

 2862. 

 2863.. 

 2874 « 

 2877., 

 3033. 

 3213. 



3223. 

 3231 o 

 3232. 

 32340 



Near Unalaska 



Near Shumagln Islands, Alaska 



Near Afognak Island, Alaska 



Off Vancouver Island, British Columbia. 



Admiralty Inlet, Washington 



Ofl Cape Flattery, Washington 



.do. 



neceta Bank, Oregon 



South or Alaskan Peninsula (Sannak 

 Islands). 



Near Unalaska 



Bristol Bay, Alaska 



do 



-do. 



n T!iese specimens are ali 



pebbles 



green mud 



gray sand, gravel 



gray sand and pebbles 



pebbles 



rocks and shells 



black sand and mud 



coral, broken shells, rocky 

 black sand 



black pebbles 



stones 



stones, pebbles 



sand, pebbles 



more or less Intermediate. 



U. S. Nat. Mua. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 

 Do. 



