ASTEUOIDEA OF NORTH PACIFIC AND ADJACENT WATERS — FISHER. 231 



bearing pedicellaria' and lonjrer, sharper spines. The unarnie<l surface of the mar- 

 ginal plates is much more extensive in nnnata. 



In some respects annata may he considered as an intermediate form between 

 phrygiana and hiopeltO: It is certainly much nearer the latter, however, and per- 

 haps should be ranked as a full species. It shows such obvious resemblances to 

 leiopelta, which furthermore exhibits certain characters of armata (as, for instance, 

 the marginal spiiacs) in a rudimentary condition, that a subsi)ecific designation is 

 believed to best indicate the relationship. 



The relationshij) between armata ami Icurilensis is not clear. They both range 

 together at stations 480.3 and 4804, and several specimens of kiirilensis seem to have 

 an infusion of annata blood, as if hybridism hail occurred. These intermediates 

 are nearer kurileitsis, however, and I do not think that they are genuine intcrgrading 

 forms between Jcuiilensis and armata. The jiossibility of leiopelta being connected 

 with spinosa through this series must be considered, however improbable it may 

 seem from the great difference of the extreme forms. Future exploration will ])rob- 

 ably tend to multiply rather than lessen the number of species of Uippasterla in the 

 North Pacific. 



mPPASTERIA HEATHI Fisher. 



PI. 44, figs. 1, 2r pi. 58, figs. 5, 5a; pi. 60, fig. 6. 

 Hippasteria heathi Fisher, Hull. Bur. Fisheries for 1904, vol. 24, June 10, 1905, p. 309. 



Diagjtosis. — Rays five. R = 78 mm.; r = 39 mm.; R=2 r. Breadth of ray at 

 base, 42 mm. General form robust; disk large, rays broad, evenly tapered from 

 a wide base to a blunt recurved extremity. Abactinal surface considerably inflated; 

 a well-defined interradial sulcus leading from marginal plates three-fourths of 

 distance to center of disk. Interbracliial arcs wide, shallow. Abactinal surface 

 covered ■with robust widely spaced conical spines and more numerous large, low, 

 bivalved pedicellariic; abactinal granules unequal, small, scattered, immersed in a 

 soft meftibrane that obscures entirely the outlines of plates; abactinal skeleton 

 fenestrated; papula) all over abactinal surface large; marginal plates small, most 

 of them with a large bivalved petlicellaria, one to four promment conical spines 

 and unequal conical granules in one or more series about the margin. Adamhulacral 

 plates with two stout blunt furrow and two actinal spmes. Actinal intermediate 

 areas with unequal, irregular plates bearing large bivalved pedicellariw and stout 

 tubercular spines and granules. 



Description. — Abactinal surface beset with mdely spaced, robust, rigid, taper- 

 ing, upright, bluntly pointed spines, 3.5 or 4 mm. in length; one, or rarely two, 

 to the larger rather ^videly separated primary plates; the median radial and either 

 adradial series of spines extending to tip of ray, but very h-regularly; the other 

 spines too irregularly distributed to form rows. Scattered all over abactinal 

 surface are many sessile, large, low bivalved pedicellariae with smooth edges to the 

 jaws. These pedicellaria; (wliich have a base 1.5 to 3.5 mm. in length, a diameter 

 of 1.5 mm., and a height a trifle less than 1 mm.) are more numerous than the 

 conical spines, and are borne on the primary abactmal plates, usually occup^-ing 

 all the elevatc'l surface. A comparatively few small ones are borne on the lai^er 

 secondary plates. The primary plates are not well defined and circular with a 



