\>TKl;omi. \ 01 SORTS PACIFIC \\l> IDJACEN1 WATERS il-lll.l; -'•> 



marginal and actinal Beriee normally quite regular; sometimes a short intermarginal 

 series of Bpinee; adambulaoral - j >i 1 1 <■ - alternating irregular!] one and two; unguiculate 

 straight pedicellariae in the intermarginal and lateral channels and also sometimes 

 abactinally and on proximal furrow Bpii 



Description There are 12 specimens of Mr. Murdoch's type Beriee from 

 fathoms LO miles west of Point Franklin, Arctic Ocean No 7626 I ^ \ \1 . ranging 

 in size from B 4 mm. to K 36 nun. Forma ttains B 73 mm., station 



3442 The abactinal spines are coarse in relation t" the size of the ray, oot fine; 

 not uniform in si/.c: very distinctly spaced, oot crowded. Neither are tl larly 



arranged in cither transverse or longitudinal Beriee. But there is a verj distinct, 

 irregular, even zigzag, radial row <>f larger Bpinee in most of tin 1 specimens and a 

 certain linear arrangement may be noted in the spinelets adjacent to the supero- 

 marginals. The Bpinee arc short and decidedly blunt; the larger, about as high as 

 broad, arc subcapitate, with evenly rounded or subtruncate, finely striated t i | > — ; 

 the smaller are less capitate, cylindrical or slightly swollen with fewer striae and 

 less regular tips. The spines are surrounded at mid beight, <u- near the tip-. l>\ a 

 ureatli of crossed pedicellariae, the numbers of which are subject to individual and 

 locality variation. They are more numerous in Forma h -. In some alcoholic 



specimens the crown- of pedicellariae nearly or quite touch but not in the typi 



The superomarginal spines are distinguishable by their regularity rather than 

 by their slightly greater length. They are clavate, finely striated and relatively 



slenderer than the radial spines, as well as actually slightly longer. The series curves 



upward t<> the interradial angle and the mtermarginal furrow is lure a bit wider. 

 and sometimes occupied by a short Beries of intermarginal spinelets which arise from 

 the descending lobe of the plate. The character is variable. Rarely there is also 

 a spine on the upper lobe of the plate, or a transverse series of three; station 3559. 



There are no interiuaiirinal plates. 



The inferomarginal spines are still longer, and a little stouter than the supero- 



marginals, sometimes a little benl upward, subterete to clavate in form (in variants 



sometimes compressed, and much more robust than in the type \aint\ Both 



series have rough-tipped spines, and oircumapinal wreaths of pedicellariae or half- 

 wreaths on the inferomarginals of small specimens). There is one short series of 

 smaller, hut similar, actinal spines. The length of tin' Beries varies with age; in the 



largest Point Franklin specimen it is half the length of furrow. In the largest examples 

 the series reaches two-thirds to three-fourths the length of the lay. 



The adambulacral Bpines are close-set, slender, terete, blunt, and stand one or 

 two to a plate in irregular alternation. The proximal 8 or in plates are usually 

 monacanthid, sporadically diplacanthid. About three post-oral adambulacral pi 

 are in contact These apparently always have hut one -pine each. The inner of 

 the two adambulacral Bpines i- generally slenderer and is bent over tin- furrow in some 

 examples. It seems to he the onlj on,' which regularlj carries Btraight pedicellariae 

 very variable in number, and absent in small specimens). Both spines have clusl 

 of crossed pedicellariae. Some of the-.' differ in detail from the abactinal crossed 



pedicellariae. as the jaw when \iewed in profile possesses S longer terminal expanded 



lip, with in. >re teeth s.e pi. 10, iiu r - 2, 2a, :>. :;•/. I The pedicellaria is rather more 



tapered toward the elld. 



