ASTEROIDEA OF NORTH PACIFIC AND ADJACENT WATERS FISHER. 75 



set at a considerably higher level when animal is viewed from actinal side than 

 is that of the adambulacral plates; that is, the plates are verj- prominent. 



Actinal interradial areas small, the plates extending to twentieth or twenty- 

 second inferomarginal; or a little less to a little more than two-thirds length of 

 ray. The plates adjacent to adarabulacrals are largest, and the arrangement is 

 in irregular rows between the adambidacral and inferomarginal plates, there being 

 more or less variation in details." In the Californian specimens, which are smaller 

 than Ludwig's material (from Gulf of Panama), the plates on the ray are not so 

 regular as in his figure 102, there seldom being two intermediate plates of the e.xternal 

 series corresponding to one in the series adjacent to adambulacrals. Usually there 

 is but one. The difference in size may account for this. The i)lates are beset with 

 compact groups of very fleshy spatulate round-tipped papilla^, which become pressed 

 into various shapes by mutual contact. The calcareous spinelet within the pa])illa 

 is delicate, subcylindrical, tnmcated, sometimes flattened at tij). The number 

 of papillae to each plate varies, and they are so compactly arranged that if the 

 prevalent slime is thoroughly cleaned off, the outlines of the groups in the inter- 

 radial areas are clearly distinguishable. At the outer end of the mouth plates are 

 a few isolated papillae resembling in shape a flattened grain of corn attached by the 

 small end. In Bathyhiaster pallidus Danielssen and Koren describe such groups 

 of spinelets as pedicellarise. In the present species although the compact grouping 

 may suggest pedicellarisf, it is not at all likely that the spinelets subserve any such 

 function. Structurally they are no more to be considered as pedicellarise than 

 are ordinary paxillse. 



Madreporic body small, broadly oval, situated a little to the outer side of a 

 point midway between center and margin of disk. Striations coarse and inter- 

 rupted, radiating from the adcentral side of plate. The ridges are occasionally 

 branched. 



Anatomical notes. — Superambulacral plates well developed, but absent from 

 first two ambulacral plates and from about the last twelve which are small and 

 crowded against marginals. All except the two first superambulacrals extend 

 from the ambulacrals to upper end of inner surface of inferomarginals. The first 

 two meet the actinal uitermediate plates. This varies probably with the size of 

 the specimen. A very small anal opening is present to which a short intestine 

 leads from the dorsal stomach. On the side of the intestine toward madreporic 

 canal, and on the opposite side (toward anterior ray) is a digitate saccular intestinal 

 coecum which varies in shape in difl^erent individuals. In one example the cffca have 

 short very ii-regular branches, and in another four and five regular divisions, respec- 

 tively, the latter resembling glove fingers. Gonads in a tuft on either side of inter- 

 radial line, the aperature of each about 2 mm. from marginal plates in the abactinal 

 integument. Polian vesicles six, one on either side of madreporic canal, and one 

 in each of the other four interadii. Interradial septa uncalcified. 



o See Ludwig, Mem. Mus. Comp. Zool., vol. 32, 1905, pi. 19, fig. 106. 



