182 A. M Verrili — Revision Genera mid Species of Starfishes. 



The abactinal plates become suddenly reduced to three radial 

 rows, about opposite the fourth or fifth pairs of marginal plates, and 

 a little farther out onl}'- the median row remains ; this disappears 

 about opposite the ninth pair of plates, beyond which the nine distal 

 pairs of marginal plates are in contact medially. The apical plate 

 is rather small, subconical, prominent. The papular pores are small 

 and scattered singly over large baso-radial areas. 



The actinal interradial plates are angular and polygonal, rather 

 large, closely crowded together, forming rows parallel with the 

 ambulacra; they are covered with large, crowded, rounded granules; 

 most of them have, also, a single, large, oblong or elliptical, valvular 

 pedicellaria, usually occupying about one-half the width of the plate. 



The adambulacral plates have each four or five, short, stout, blunt, 

 angular or prismatic spines in the furrow-series, placed in a regular 

 row; next to these, on the actinal surface, there is also a row of three 

 similar, but shorter, compressed spinules ; on the outer end there are 

 one or two rows of smaller and shorter, thick spinules ; a large val- 

 vular pedicellaria usually occupies the center of the plate, but when 

 it is absent there is a central row of spinules, making four rows on 

 the actinal surface. 



The dentary plates are large ; each one, of a pair, bears about five 

 stout, blunt, prismatic or compressed spinules in the furrow series, 

 and two rows of short, thick, obtuse spinules on the actinal surface, 

 those next the mouth being largest ; at the apex of the jaw there 

 are two larger, thick, blunt, prismatic and compressed spines. 



Lesser radius, 25™™ ; greater radius, '75'°'^, Taken by the Blake 

 Expedition, in the West Indies. 



This fine species appears to be closely allied to M. pedicellaris. 

 It is referred to the genus Mediaster with some doubt, for the char- 

 acter of the abactinal skeletal plates could not be satisfactorily 

 ascertained by an external study of the single alcoholic specimen, 



Mediaster (?) pedicellaris Verrili. 



Goniodiscus pedicellaris Perrier, Nouv. Arch, du Miis., vi, p. 245, pi. iv, fig. 

 3, 1884. Sladen, op. cit., p. 756, 1889. 



The following notes were made upon one of the original types of 

 Perrier, in the Museum of Comp. Zoology, 



Radii as 7:19, Dorsal or abactinal plates, large, roundish, the 

 summit convex when naked, but flat when covered with the spinules; 

 the largest have about sixteen marginal, tapered, acute spinules, and 

 one to five or more somewhat larger acute central ones. Intervening 



