102 THE VOYAGE OF H.M.S. CHALLENGER 



structure, I have considered it desirable to place them apart ; the value of the characters, 

 in the present state of our knowledge of the Plutonaster group of species, appearing to 

 justify their being ranked as a subgenus. 



1. Tetinjaster subinermis, Philippi, sp. 



Asterias subinermis, Philippi, Archiv f. Naturgesch. Jahrg. iii. Bd. i. 1837, p. 193. 



Astropecten subinermis, Miiller and Troschel, System der Asteriden, 1842, p. 74. 



Archaster subinermis, Perrier, Nouv. Archives Mus. Hist. Nat., 2 e S6r. 1878, t. i., pp. 33, 57, 88. 



Localities. — The Mediterranean area. (Algiers, Naples, Nice, Messina, Sicily.) 



2. Tethyaster 'parelii, Dtiben and Koren, sp. 



Astropecten Parelii, Diiben and Koren, K. Svensk. Yet.-Akad. Handl., Ar 1844 (Stockholm, 1846), 



p. 247, tab. vii. figs. 14-16. 

 Archaster Parelii, Sars, Oversigt af Norges Echinodermer, Christiania, 1861, p. 35, tab. 3, figs. 1 and 2. 



Localities — " Porcupine " Expedition : 



Station 31. Between the north of Ireland and Rockall. Lat. 56° 15' N., long. 

 11° 25' W. Depth 1360 fathoms. Bottom temperature 2°'9 C. ; surface temperature 

 13°'8C. 



In Sir Wyville Thomson's popularly written Depths of the Sea, the occurrence of this 

 species is specially mentioned on at least two other occasions (loc. cit., pp. 122, 181), but 

 the exact localities are not given, and I have not seen any other specimens in the collec- 

 tions placed in my hands excepting the one under notice. 



Other localities. — Finmark, Lofoten, Coast of Norway, off Shetland. 



Genus Lonchotaster, Sladen. 



Lonchotaster, Sladen in Narr. Chall. Exp., 1885, vol. i. p. 609. 



Disk rather large. Bays moderately elongate and comparatively narrow, tapering to a 

 finely pointed extremity. Interbrachial arcs wide and openly rounded. 



Marginal plates small, short, and numerous, more or less confined to the lateral wall 

 of the ray. Supero-marginal plates smaller than those of the inferior series. Infero- 

 marginal plates short and broad. The plates of both series covered with low granule-like 

 papillae, often somewhat squamiform, invested more or less with membrane (succulate). 

 No prominent spines on either series. Large incipient pedicellarian apparatus on most of 

 the infero-marginal plates, and on some of the plates of the superior series. 



Abactinal area with numerous small closely-packed paxillse, composed of small, erect, 

 skin-covered papilla?, and often bearing a pedicellarian apparatus. Abactinal plating 

 circular. The paxilloe present no definite order of arrangement. Papulse regularly- 

 distributed. 



