Boone, Echinodermata, Cruises of "Eagle" and "Ara," 1921-28 105 



arms. The genital slits are small and do not have a margin of grains ; 

 their long diameter is 5.5 mm. The tentacle scales are very fine, 

 slender, spine-like. They are not to be found within the ninth fork, 

 occasionally the tenth fork, of the arm on its main trunk; beyond 

 this point there are one, two, three, sometimes four to each pore, the 

 number being greatest on the smaller side branches ; however, on the 

 finer twigs the number decreases and on the finest twigs the tentacle 

 scales are replaced by a single hook. 

 References: Euryale muricatum Lamarck, Anim. d. sans Vert., II, 



p. 538, 1816; second edition, vol. Ill, p. 217, 1840. 

 Astrophyton muricatum Agassiz, Mem. de la Soc. des Sciences Nat. 



Neuchatel, p. 12, 1839. — Muller and Troschel, Syst. der Asteri- 



den, p. 122, 1842. — Lutken, Kongl. Danske Vidensk. Selsk. 



Skrift., 5th Raekke, Bd. 5, p. 258, 1861.— Doderlein, Japan. 



Euryalae, pi. 5, fig. 1, 1911. — H. L. Clark, Mem. Mus. Comp. 



Zool., XXV, p. 188, 1915. 

 Astrophyton costosum Lyman, Mem. Mus. Comp. Zool., vol. I, p. 192, 



1865. 



GNATHOPIURIDA. 

 Family: AMPHIURIDAE. 



Genus: AMPHUBA Forbes. 

 Amphiura diomedeae Lutken and Mortensen. 



Plate 61. 



Type: The type series of this species was taken by the "Albatross" 

 at stations 3393, 1020 fms., 3394 in 511 fms., at 3398 in 1573 fms., 

 and at 3429 in 919 fms. Deposited in the United States National 

 Museum and the Museum of Comparative Zoology. 



Distribution-. As cited above, in deep water off the Pacific coast 

 of Panama; also taken by the "Albatross" at numerous stations in 

 large numbers along the Japanese coast in 56 to 726 fms. Bathymetric 

 occurrence: 56 to 1723 fms. 



Material examined : Two disks with broken arms attached and 50 

 to 100 arms minus disks, collected in 100 fms., Punta Arenas, Costa 

 Rica, by the "Ara," Cat. no. 292. 



Color : The color of the living animal is not recorded. 



Life history: Unknown. 



Technical description : Disk diameter 10 mm., arm length 46 mm. 

 Abactinal surface paved with irregular scales, the primaries of which 

 are well defined. Interbrachial regions of actinal surface of disk 



