Boone, Echinodermata, Cruises of "Eagle" and "Ara," 1921-28 119 



Family : OPHIOLEPIDIDAE. 



Genus : OPHIXJRA Lamarck. 

 Ophiura sarsii Lutken. 



Plate 71. 



Type : Lutken 's type material came from Scandinavian waters and 

 is deposited in the Copenhagen Museum. 



Distribution: This species has a remarkable bathymetric occur- 

 rence, ranging from 20 to 3123 meters. It is widely distributed in 

 the Arctic and subarctic regions of Europe, Asia and America, 

 having been recorded from the Russian and Scandinavian coasts, 

 southward to the Faroes and Heligoland in the North Sea ; in Green- 

 land ; on the east American coast down to Cape Hatteras, N. C, across 

 the American Arctic and down to California on the American Pacific 

 coast, and on the Asiatic coast down to Japan. 



Material examined: One specimen, collected at Eastport, Maine, 

 by the "Eagle," Cat. no. 297. 



Color: See Koehler's color plate in the Report on the Echinoderms 

 secured by the "Princess Alice." The brittle star is dark red or 

 nearly red-brown and is often maculated. 



Life history: Unknown. Dr. Mortensen suggests that Ophioplu- 

 teus compressus may be the larva of 0. sarsi. In growth this latter 

 species appears to be similar to the European 0. texturata. 



Parasites : A curious undescribed organism of sac-like form, which 

 attacks and destroys the genital organs of the brittle star, has been 

 recorded as especially abundant in Trondhjem Fjord by Dr. Mor- 

 tensen. Isn't this parasite a Rhizocephalid crustacean? 



Technical description : The specimen figured has a disk diameter 

 of 26 mm. ; arm length, tip incomplete, 64 mm. and is about five to 

 six years old. The abactinal surface is covered with rather coarse 

 irregular scales; the primaries of which are usually distinct. The 

 radial shields are half, or scarcely half of the disk radius, widest 

 just above the dorsal arm-plate where they are contiguous or slightly 

 separated, approximately broad pear-seed shaped with the apices 

 directed inward, or sometimes nearly circular. The outer arm-comb 

 bears 9 to 14 short, stout, conic papillae. The interbrachial spaces 

 of the actinal surface are paved with irregular large, coarse scales, 

 those near the circumference being the larger. The mouth-shields are 

 large, somewhat shield-shaped, with the outer margin rounded, the 

 side margins a little concave, the inner margins meeting in an angle. 



