Boone, Echinodermata, Cruises of "Eagle" and "Ara," 1921-28 99 



and the arms are encased in a tough thick skin, which also extends 

 out upon the mouth-plate and side mouth-plates concealing them, 

 reaching to the bases of the mouth papillae. There are eight mouth 

 papillae set in regular series; each papilla is large, squarish, with 

 the outer margin convex and finely crenulate. There are five or six 

 teeth, each a broad, bluntly rounded lobe with its margin finely 

 serrate. The genital slits which begin outside the mouth-shield extend 

 about 55 per centum of the width of the interbrachial region. The 

 arms are rounded, rather thick proximally, the arm-plates imperfectly 

 developed and concealed beneath the tough skin which encases the 

 entire arm. The arm-spines are in series of four, short, stocky, nearly 

 equal, encased in skin at the base and with the tip thorny. There 

 are no tentacle scales. 

 References: Ophiura pentagona Lamarck, Hist. Anim. sans Vert., 



vol. II, p. 546, 1816. 

 Stella pentagona scolopendroides regularis Linck, De Stell. Marin., 



p. 51, pi. 27, fig. 46, 1733. 

 Ophiomyxa pentagona Muller and Troschel, Syst. Ast., p. 108, 1842. 

 — Lyman, Illus. Cat. Mus. Comp. Zool., Memoirs, vol. I, p. 180, 

 1865 ; Bull. Mus. Comp. Zool., vol. Ill, part 10, p. 272, pi. 7, fig. 

 18, 1871-76.— Rept. Voyage "Challenger," Zool., vol. V, p. 246, 

 1873-76.— Ludwig, H., Zeits, fur Wissen Zoologie, vol. XXXI, 

 p. 383, 1878; Echin. des Mittelmeeres, Mitt. Zool. Sta. Neapel, 

 Bd. I, p. 552, 1879.— H. L. Clark, Mem. Mus. Comp. Zool., XXV, 

 p. 169, 1915. 



Family : ASTERON YCHIDAE. 



Genus : ASTERONYX Muller and Troschel. 



Asteronyx loveni Muller and Troschel. 



Plate 59. 



Type: The type of this species came from Bohuslan and Hammer- 

 fest, Norway, and is deposited at the Museum at Stockholm. 



Distribution : This species is nearly cosmopolitan in its distribu- 

 tion, being known in Europe from the Scandinavian Seas to Finmark, 

 also off Scotland and southwest Ireland; on the American east coast 

 from Labrador down to the lower "West Indies ; on the African coast 

 down to the Cape of Good Hope ; also in the Indian Ocean, and in the 

 Pacific Ocean from Australia to the Bering Sea. Bathymetric occur- 

 rence : 100 to 1800 meters. 



