464 THE VOYAGE OF H.M.S. CHALLENGER. 
B. Bathymetrical range: 101 to 632 fathoms. 
y. Nature of the Sea-bottom: Brown mud (Payer); Coarse granular clay, and grey 
sandy clay (Danielssen and Koren). 
Chorological Synopsis of the Species. 
Ocean. | Range in Fathoms. Nature of the Sea-bottom. 
Korethraster hispidus . , Atlantic. 101 to 632 Mud ; Clay (coarse and sandy). 
1. Korethraster hispidus, Wyville Thomson (Pl. LXXX. figs. 6-9). 
Korethraster hispidus, Wyville Thomson, 1873, The Depths of the Sea, pp. 119, 120, fig. 15. 
Locality.— Porcupine” Expedition : 
Station 57, 1869. In the Faerée Channel. Lat. 60° 14’ N., long. 6° 17’ W. Depth 
632 fathoms. Bottom temperature —0°°8 C.; surface temperature 11°:1 C. 
Remarks.—This species has been so fully and ably described by Danielssen and Koren, 
and previously by von Marenzeller,’ that I consider it superfluous to re-describe the 
species. Through the kindness of Dr von Marenzeller I have examined the example col- 
lected during the ‘“ Tegetthoff” Expedition by Mr Julius Payer, and I can confirm the 
accuracy of his determination. I have therefore limited myself to giving an illustration 
of the original example dredged by the “ Porcupine”; and I have included in the fore- 
going generic diagnosis reference to several points of structure which appear to have escaped 
the notice of previous observers. 
Genus Peribolaster, Sladen. 
Peribolaster, Sladen in Narr. Chall. Exp., 1885, vol. i. p. 616. 
Form stellate. Rays rather short and broad. Disk large, more or less inflated. 
Abactinal surface convex. Actinal surface plane. Margin angular. Interbrachial ares 
acute. 
Abactinal surface with cruciform plates having delicate prolongations or supplementary 
trabecule, which impinge on the adjacent plates, and form a regular network with large 
quadrangular meshes over the entire surface. On the centre of each abactinal plate is 
borne on a small boss a fascicule of delicate, equal spinelets, the spinelets being enveloped 
in membranous sheaths which are united in the interior of the fascicule. The fascicules 
are isolated and well spaced. Several papulz are present in each interspace or mesh. 
Den Norske Nordhays-Expedition 1876-1878, Zoologi, xi. Asteroidea, 1884, p. 95, tab. xii. 
* Denkschr. d. k. Akad. d. Wiss. Wien, math.-naturw. Cl., 1877, Bd. xxxv., p. 283, 
