A. E. Verrill — Mevision Genera and ISpecies of Starfishes. 211 



Plutonaster Agassizii Verrill. 



Archaster Agassizii Verrill, Anier. Journal Sci., vol. xx, p. 403, 1880. 

 Plutonaster rigidus Sladen, op. cit., p. 91, pi. xiv, figs. 3, 4 ; pi. xv, figs. 3, 4, 



1889 ; also var. semiarmatus, op. cit., p. 94. 

 Plutonaster bifrons (jyars) Sladen, op. cit., p. 88, 1889 (very young example). 

 Plutonaster Agassizii Verrill, Proc. Nat. Miis., vol. xvii, p. 248, 1894. Amer. 



Journ. Sci., xlix, p. 131, 1895. 



Plate XXVII. Figure 6. 



This species is intimately related to P. bifrons and other forms 

 that have been described from the East Atlantic. Probably several 

 of these species will have to be united eventuall}^ It is also very 

 closely allied to P. mtermedhis (Per.) of the West Indies, with 

 which I have compared it. From the latter it appears, however, to 

 be distinct. 



Our specimens occasionally have one or two small })edicellariae on 

 the actinal side near the jaws (see pi. xxvii, tig. 6). They have 

 three or four simple papilliform blades, and are very similar to the 

 ordinary form found on Dytaster. 



Perrier and Sladen both state that no pedicellaria^ are found in 

 this genus. 



Four-rayed and six-rayed specimens occasionally occur. 



Taken at 103 stations between ¥. lat. 41° 53' and 35° 45' 23"; in 

 182 to 1700 fathoms. Most common in 300 to 1200 fathoms. 



Plutonaster eflaorescens Perrier. 



Archaster efflorescens Perrier, Etoiles de Mer, p. 255, 1887. 



Plutonaster efflorescens Perrier, Trav. et Talism., p. 322, 1894. . 



The type of this species from station 29, 955 fathoms, Blake Ex- 

 pedition, when examined by me in 1896, was in a very poor state of 

 presex-vation ; all the rays but one were broken off and the granules 

 of the disk Avere largely rubbed off. 



It is a young specimen. The radii are only 17'"'" and 5-5™''\ so 

 that the adult specific characters ai-e not developed. 



The rays are relatively large for so young a specimen, slender, 

 tapered, and narrow distally, being more like those of Dytaster than 

 Plutonaster. 



Mai-ginal plates are 34 to 36 on each side of the body, small, 

 squarish, not oblique ; the upper ones extend a little on the actinal 

 side of the disk. They are covered with minute raised spinules, 

 which are not crowded ; along the interradial margins each usually 

 bears a slender tapered, conical spine, about as long as the breadth 

 of the plate. The marginal plates are convex with a distinct groove 

 between them. 



