316 KFLLETIN OF THE BUREAU OF FISHERIES. 



among which are scattered numerous forficiform pedicellarhe, longer than the spinelets. and of course 

 much more robust; median radial series of plates more prominent than the rest and each bearing on a 

 central prominence a thimble-shaped tubercle; abactinal and lateral faces of the ray gradually confluent 

 by a well -mil in led margin, the superomarginal plates not being prominent in any way; between supero- 

 marginal and adambulacral plates.") longitudinal series of exactly similar plates — an inferomarginal and 

 4 actinal intermediate series — and all precisely similar to the superomarginals; on outer portion of ray 

 the intermediate series successively reduced to 3, 2, and finally, at end of ray, to 1 ; each of these plates, 

 including the 2 marginal series, bearing a very slender, delicate, sharp spinule, which increases in 

 length toward the furrow, that on the proximal superomarginals being 2 nun. in length and that 

 nearest the furrow on the same transverse series nearly 4 mm.; general surface of the plates covered 

 with very delicate, short, spaced, often curved spinelets. and having 1 or 2 rather prominent pedicel- 

 larise to each plate, forming fairly regular longitudinal rows along the ray, between successive series of 

 plates; median radial plates hearing 2 to 5 pedicellarise each; papulae inconspicuous, 1 or 2 to the pore, 

 usually 1; papular areas very small. 



The prominent adambulacral plates with a transverse series of 3-5 spinelets; the inner 2 short, 

 stout, and pointed, and borne on the furrow projection; the innermost with a terminal membranous 

 expansion bearing 6 or 8 pedicellarise of graduated sizes, the second with 1 similar, much larger 

 pedicellaria, or occasionally 2, near the base of the spinelel ; the next, or first actinal spinelet, longer 

 and slender and pointed, the 2 following being successively shorter; on outer part of ray only 2 actinal 

 spinelets commonly present, and the second furrow spinelet often missing. The alternate non- 

 prominent plates have a small furrow spinelet, hearing 1 or 2 small pedicellaria', situated near the 

 adoral edge, and on tin- actinal surface a transverse row of 2 spinelets very similar to those of the 

 prominent plates; a large pedicellaria sometimes stands at the outer end of the series. 



Madreporic body convex, subtubercular, circular, situated 7 mm. from center of disk. 



Locality: Stat inn 4.'!s7 off San Diego, Cal. (longitude of Point ( 'once) it ion ), 1,059 fins., mud. 



Myxoderma, new subgenus. 



Differs from typical Zoroaster in having smaller median radial plates, either cruciform or sub- 

 stellate, and irregular adradial plates which are uot compactly placed, hut form an irregular, open. 

 subreticulate skeleton at the base of the ray, leaving comparatively large papular areas, which have 

 2-4 papul.-e. There are 3 series of intermediate plates between the inferomarginal and adambulacral 

 series, instead of 4 as in Zoroaster. Spinelets land in type species the spines also) invested with a 

 pulpy sacculus, giving them a very rolmst, flabby, papilliform appearance. Type, Zoroaster (Myxo- 

 derma) sacculatus, new species. 



Zoroaster (Myxoderma) sacculatus, new species. 



Rays 5. 1! = 200 mm.; r = 17 mm. R = 11.7 r. Breadth of ray at base, 22 mm. 



I»isk convex; rays sulicylinilrical. robust, hut slender, tapering from a narrow base to a pointed 

 extremity, which is capped by a large terminal plate; all the plates spiniferous; membranous invest- 

 ment of spines ami spinelets, thick, fleshy, and saccular; interbrachial angles very acute. In life the 

 whole animal is very slimy. 



(In the proximal portion of the rays and on disk the abactinal skeleton is comparatively very 

 open and subreticulate; plates cruciform and stellate, with fairly long processes by which they are 

 joined, leaving extensive subquadrate papular areas; plates becoming less markedly lobed on the 

 sides ami ventrolateral region of the ray, and the papular areas then reduced in size as in typical 

 Zoroaster; primary basals and radials stellate, their processes touching and slightly overlapping, and 

 joining also the irregularly cruciform under basals; papular areas very wide in proportion to the plates, 

 quadrate or triangular in shape; disk plates hearing a number of short, compressed, blunt spinules, 

 articulated to rounded busses on the surface. In life they, as well as the general surface of the plates, 

 are covered with a thick, fleshy, rather viscous membrane. Prominent pedicellarise thickly scattered 

 nver the disk, principally in the papular areas; abactinal skeleton of rays very open, and subreticulate, 

 the lateral and actinal more nearly as in typical Zoroaster; median radial series of plates fairly regular, 

 cruciform or rarely stellate, a trifle larger than the superomarginal plates, which are also cruciform, 

 but shorter: between these two series, on either side, a very irregular longitudinal series of smaller 

 triradiate or cruciform plates, which articulate and usually imbricate with the processes of the radial 



