L8TBR0IDBA 01 NORTB PACIFIC wi> ADJACKN1 w i-Hhic 1_'7 



plates small, reaching to middle of ray; ■ ten rudimentary 

 tend u short distance beyond middle, (PI. 48, fig 



Madreporic bod; situated at the middle of r. conspicui 'btly convex, with 



rather fine branched radiating Btriae It i- encircled by ■ variable number "f 

 Bpinelets. 



Variation*. Form* aUukent The typical farm which has jusl been described 

 is rather variable, especially in the western part of its rang* r i of 



specimens bom s series of localities, extending from Kodiak westward t«> Attn. 

 reveals s gradual change in addition to local peculiaritii 



Western examples gradually become larger and then tendency for tin' 



ninji>r abaotmal Bpines to form aggregates of tw.. t<> five, to become incipiently 

 "acervate," bo thai the abactanal surface is uneven, nol rather even as is the con- 

 dition in Kodiak and most Unalaakan examples. The bivalved pedicellariae, which 

 nt Kodiak are fairly well developed, become larger and heavier, and reach t heir 

 development from (Jnalaska to Adakh. To the westward of Adakh they decn 

 in Dumben and in breadth. Attn and Agattu examples in this character arc inter- 

 mediate w ith asiatiea. 



rZodiak [aland: The BpecimenB in respect to Btraight pedicellariae are inter- 

 mediate between L. alath and /.. alaskm - - alaslcentis. The lateral 

 bivalved pedicellariae are distinctly MimlltT than in examples from tli« j Aleutian 

 Inlands, rlarluk examples, on the whole, have more spinelets, the Buperomaiginals 

 carrying two or three Bpinelets. (PI. 56, fig. 2.) These specimens favor n ufttaji 

 Some of them resemble pribilqfengis l>nt have narrower Btraight pedicellariae. 

 1'anl examples have fewer, more widely Bpaced spinelets, in common with otl 

 from Seldovia, Porl Graham, Kukak Bay, and the Shumagin [alands All tl 

 have weaker spinelets than typical [Jnalaskan examples, and usually only one Bupero- 

 marginal Bpinelet, l>nt here and there two. The straight pedicellariae are smaller than 

 QormaL They intergrade freely with typical alaskent Set fori . 



[Jnalaska: Type locality. At [Jnalaska the specimens frequently have the 

 larger abactmal Bpines in groups of two to f<>nr or even five ly in the earinal 



Belies The pedicellariae are well developed, with wide jaws and have a rounded 



often irregularly denticulate distal mar 



Atka: The specimens are characterised by the prominence of mhbI1 prm/. 



scattered ahaetinal spinelets and l»y rather greater disparity between the lartre-t and 



smallest dorsal spinelets There i~ considerable variation in the number of bivalved 



pedicellariae The proximal in fero marginal plates n-nally carry only one spit 



the distal two. The actinal Beries of Bpinelets is absent or quite short. In com- 

 parison with an average example from Kodiak, the Bpinulation sr, much 

 coarser, and much less uniform. 



Adakh: The specimens from Adakh. another island of the Andreanof group, 

 mble those from Atka. but there are also pecimens taken July 5, - 



whnli nave the ahaetinal Bpinelets almost exactly typical The largest has R S3 mm, 



Like tl then, it has M typical Dumber of marginal Bpinelets and the actinal b> 



nds half the length of the ray All the spinelets are quite stout, Inn the marginal 

 and ventral especially -■'. these being heavy, clavate, ">r even clavate-spatu 

 The bivalved pedicellariae are numerous and large, t he jaw - being \ ery often ■ •.' 



