248 NEW STARFISHES AND OPHiniANS—VERRILL. vol.xvii. 



paxillaj are larger tliau in either of our other species; mauy have a 

 slender central spine. The papular areas are small, rounded, and have 

 few large pores. The genital openings are far apart, about opposite 

 the distal third of the first pair of marginal xdates and close to them. 

 The upper marginal plates of the first pair are rounded and smaller 

 than those that follow them, but the corresponding lower ones are dis- 

 tinctly larger and more swollen on the under side than those that suc- 

 ceed them. There is only one large stout spine on the actinal side of 

 the adambulacral plates. 



This occurred in 368 to 858 fathoms. 



Subfamily Plutonastertn^, S 1 a d e n . 



DYTASTER GEANDIS, V e rril 1. 



Archaster grandis, Verrill, Amer. Journ. Science, xxviii, p. 218, 1884. 

 Dyiasicr madreporifer, Sladen, op. cit., p. 70, \\\. 3, figs. 3, 4; pi. 32, figs. 5,6, 

 1889. 



This species is clearly identical with that so well described and 

 figured by Sladen, but his specimens were not full grown. 



Our large series includes all sizes from the young 10mm. in diameter 

 up to large ones 260 mm. in diameter. The very young specimens are 

 widely different from the adults, but specimens 50 mm. in diameter 

 have the general characters of the adults. 



This species, and probably others of the genus, have well-developed 

 superambulacral plates, which would, perhaps, indicate special affini- 

 ties with the Astropectinidae were not such plates present in several 

 other widely different genera. 



A few regular four-rayed examples have been taken. This species 

 was taken in 384 to 2,620 fathoms. 



PLUTONASTER AGASSIZII, Verrill. 



Archaster agassisH, Verrill, Amer. .Tonru. Scieuce, xx, p. 403, 1880. 

 Phitonaster rigidus, Sladen, op. cit., p. 91, pi. 14, figs. 3, 4; pi. 15, figs. 3, 4, 1889; 



also var. semiarmata, op. cit., p. 94. 

 rintonaster hifrons (part), Sladen, oj>. cit., p. 88, 1889 (very young example). 



This species is closely allied to P. hifrons of Europe and P. interme- 

 dius (Perrier sp.)* of the West Indian region. It varies greatly in 

 respect to the armature of the marginal plates. In one large series 

 there are among the adult specimens all gradations from those having 

 no marginal spines whatever to those that have a large spine on nearly 

 every marginal plate of both series. Therefore it is useless to recog- 

 nize varieties based on this character, like the variety semiarmata of 

 Sladen. 



*Noiivelle8 Archives du Museum d'Hist. Nat., Ser. 2, vol. 6, p. 251, pi. vii, figs. 1, 

 2; pi. IV, fig. 4,1884. 



