A. JE. Verrill — Revision Genera and Species of Starfishes. 179 



each has an actinal row of larger spinules, similar to those of the 

 oral margin. 



This genus is closely allied to Fentagonaster, as limited by Sladen 

 and some other recent writers. The principal differences consist in 

 the somewhat more elevated and convex abactinal plates, especially 

 in the papular areas, where they are more widely separated by the 

 large papular pores and united by intervening small internal ossicles, 

 which give them a stellate appearance. On other parts of the disk, 

 as near the interradial margins, the plates are angular and closely 

 joined in a mosaic, as in the former genus. The large valvular 

 pedicellarifB are also, to some extent, characteristic, but the marginal, 

 actinal, and dentary plates and their spinules are essentially the same 

 in the two genera. The spinules on the adambulacral plates are, 

 however, more definitely triseriate, and the furrow series is more 

 differentiated in all the known species, though this is perhaps of no 

 more than specific value. 



The type inhabits the Pacific coast of North America, in rather 

 shallow water. No other species seems to have been described 

 until a second one, from deep water off our north-eastern coast, was 

 described by me in 1882, under the name of Tsasier Bairdii. Its 

 close afiinity to Mediaster was not recognized at that time, though I 

 have referred it to that genus, for several years, in my MSS. lists 

 and in the museum catalogues. 



Xediaster sequalis Stimp. 



Journ. Boston Soc. Nat. Hist., vol. vi, p. 490, pi. 23, figs. 7-11, 1857. 



Plate XXIV. Figures 10, 11, 12. 



Rays five, in length about equal to the diameter of disk, regularly 

 tapered, slender at the tip. Radii nearly as 1 : 3. Marginal plates on 

 each side of a ray 22, above and below, in a specimen having the 

 greater radius 36™'". The plates on the margin of the disk are higher 

 than wide with the intervening sutures somewhat oblique. The 

 lower marginal plates are similar in size and shape. All are closely 

 covered with small rounded granules. Abactinal areas of the rays 

 are wide at the base, where they may consist of seven or nine rows 

 of plates, but they rapidly decrease to three rows, and only the 

 median row reaches the apical plate. The papular areas are large, 

 covering nearly the whole width of the proximal half of the rays, as 

 well as most of the central disk. In these areas the plates are 

 rounded or elliptical, convex, somewhat elevated, and separated by 



