266 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



In the key to the species of OphiotJirix which he published in the 

 Challenger reports Lyman (p. 218) attributes to 0. viridi-alba nine 

 to ten arm spines, without giving any reference except to Martens' 

 description; also I do not at all understand what this same author 

 means by " tentacle scale running along outer edge of arm plate." 

 Does this mean that the tentacle scale is attached along the border of 

 the under arm plate, which is nothing remarkable and is scarcely 

 worth the trouble of recording in a synoptic table, or has Lyman 

 wished to indicate that the tentacle scale, running along the external 

 border of the arm plate, reaches the length of the latter? That is 

 what I can not understand. However that may be, 0. signata seems 

 to me very distinct from O. viridi-alba for the reasons which I have 

 just given. 



OPHIOTHRIX SPINOSISSIMA Kcehler. 



Plate 57, figs. 1, 2, 7 ; plate 101, fig. 5. 



OphiotJirix spinosissima KCEHLER ('05), p. 104, pi. 11, figs. 3-5. H. L. 

 CLARK ('15), p. 282. 



Localities. Albatross station 5108 ; China Sea, off southern Luzon ; 

 Corregidor Light bearing N. 39 E., 41.70 kilometers (22.5 miles) 

 distant (lat. 14 05' 05" N., long. 120 19' 45" E.) ; 24 meters (13 

 fathoms) ; January 15, 1908 ; Co. 



One specimen (Cat. No. 41282, U.S.N.M.). 



Albatross station 5165; Sulu (Jolo) Archipelago, Tawi Tawi 

 Group; Observation Island bearing N. 70 W., 11.86 kilometers (6.4 

 miles) distant (lat. 4 58' 20" N., long. 119 50' 30" E.) ; 16 meters 

 (9 fathoms) ; February 24, 1908 ; Co. 



One specimen (Cat. No. 41281, U.S.N.M.). 



Notes. The two specimens are of small size, as was also the type 

 upon which I established this species; in the specimen from station 

 5108, which is almost complete, the diameter of the disk is 4 mm., and 

 the arms are about 20 mm. long ; the other specimen is a little smaller, 

 and the arms are preserved for a lesser length. 



In the first individual the radial shields are very large, a little 

 larger than the second, and the covering of the dorsal surface of the 

 disk consists chiefly of club spines ending in long and fine spinules, 

 while the true spines are not at all numerous ; perhaps a certain num- 

 ber of the latter have been torn away. In the specimen from station 

 5165, on the other hand, the true spines are very numerous ; they are 

 very long and very fine, pointed at the tip and denticulate through- 

 out their whole length. 



The upper arm plates are elongated, lozenge shape, relatively a 

 litttle broader in the specimen from station 5108 than in the other, 

 and they are perceptibly elevated, or better thickened, in their distal 

 region. The under arm plates are much elongated and strongly 

 notched on their distal border. 



