HYPSELASTER. 185 



7.5 mm. wide. Petals II and IV not very divergent, slightly outwardly curved 

 at tip, about 28 mm. long by 5 mm. wide, near tip. Petals I and V very small, 

 about 7 mm. long by 3 mm. wide, with about a dozen pore-pairs on each side. 

 Genital pores, 3, rather large, those in interambulacra 3 and 4 very close together. 

 Peripetalous fasciole very distinct but lateroanal fasciole entirely wanting. 

 Periproct about 10 mm. high by 7 mm. wide. Ambulacrum III very deeply 

 sunken, and labium narrow and very projecting; as a result, the peristome is 

 nearly vertical instead of horizontal as usual. Sternum (from tip of labium) 

 nearly 40 mm. long and scarcely 14 mm. wide, closely covered with rather small 

 tubercles; while not keeled the sternum is distinctly projecting. 



Pedicellariae of two kinds were found, but of the globiferous only a single 

 specimen. This had valves .65 mm. long, not distinguishable from those of 

 fragilis. The tridentate pedicellariae, on the other hand, are exceedingly 

 abundant and very variable in size and form. The valves range from .20 to 

 .75 mm. in length and may be straight or curved. Many of those with curved 

 valves might be called rostrate pedicellariae but there is so much intergrada- 

 tion that it is better to consider them all tridentate. None of the various 

 forms appears to be significant. 



The color of the dry specimen is brown with the minute spines of the peri- 

 petalous fasciole a much darker shade, almost black. It was taken by the 

 Challenger off London River, Kerguelen Island, in 110 fms. and bears the 

 M. C. Z. Cat. No. 2953. 



More abundant material is of course necessary before the differences between 

 this species and moseleyi can be regarded as clearly fixed but there can be no 

 doubt that the Kerguelen Brisaster is distinct from the Chilean species. The 

 belief that moseleyi is a deep-water species whose range might naturally extend 

 to Kerguelen seems a mistake. The Challenger took Brisaster at Kerguelen 

 only in 110 and 120 fms. while the Gazelle did not meet with it at all. 



Hypselaster, 1 gen. nov. 



Type, Schizaster (Periaster) limicola A. Agassiz, 1878. Bull. M. C. Z., 6, p. 193. 



The genus Periaster was proposed by D'Orbigny for certain Fossil spatan- 

 goids, with which it seems erroneous to unite the Recent species of which limi- 

 cola is a type, and I have therefore selected the name Hypselaster for this latter 

 group. The presence of only two genital pores, the incompleteness or lack of 



1 'T\pr)\6s = high -f- 'aorrip = star, in allusion to the great height of the test . 



