306 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



One specimen (Cat. No. E. 171, U.S.N.M.). 



Albatross station 5582; in the vicinity of Darvel Baj 7 , Borneo; Si 

 Amil Island (N.) bearing S. 82° W., 11.5 kilometers (6.2 miles) dis- 

 tant (lat. 4° 19' 54" N., long. 110° 58' 38" E.) ; 1,628 meters (890 

 fathoms) ; September 26, 1909 ; gy. M., fne. S. 



One specimen (Cat. No. E. 170, U.S.N.M.). 



Albatross station 5585; Sibuko Bay, Borneo, and vicinity; Sipadan 

 Island (N.) bearing S. 89° W., 19.84 kilometers (12 miles) distant 

 (lat. 4° 07' 00" N., long. 118° 49' 54" E.) ; 870 meters (476 fathoms) ; 

 September 28, 1909 ; gy. M. 



One specimen (Cat. No. E. 169, U.S.N.M.). 



Albatross station 5619; Molucca Passage, Mareh Island (S.) bear- 

 ing S. 78° E., 12.97 kilometers (7 miles) distant (lat. 0° 35' 00" N., 

 long. 127° 14' 40" E.) ; 796 meters (435 fathoms) ; November 27, 

 1909 ; fne. gy. S., M. 



One specimen (Cat. No. E. 172, U.S.N.M.). 



Albatross station 5650; Gulf of Boni, Celebes; Lamulu Point bear- 

 ing N. 5° W., 23.16 kilometers (12.5 miles) distant (lat. 4° 53' 45" 

 S., long. 121° 29' 00" E.) ; 988 meters (540 fathoms) ; December 17, 

 1909 ; gn. M. 



One specimen (Cat. No. E. 173, U.S.N.M.). 



Notes. — The diameter of the disk varies between 16 mm. (in the 

 specimen from station 5619) and 26 mm. (in that from station 5348). 



H. L. Clark ('11, p. 133) has already recorded certain variations 

 observed by him in specimens of O. fastigatus from Japan, which 

 have to do principally with the form of the mouth shields and of the 

 adoral plates, as well as the number of arm spines. He finds that the 

 mouth shields, which typically are broader than long, may acquire an 

 oval outline and become as long as broad ; the arm spines are some- 

 times only two in number, but reach four in the large specimens. 

 The adoral plates are sometimes very greatly reduced and may 

 even be completely lacking when the oral plates are elongated. The 

 development of the ventral keel of the arms varies considerably. 



In five specimens from the Albatross collection I find still more 

 extensive variations, and these variations involve not only the form 

 of the mouth shields and of the ventral keel of the arms, as well 

 as the number of arm spines, but also the relative dimensions of 

 the dorsal plates of the disk and of the radial shields, and the 

 arrangement of the tentacle scales. 



Regarding the dorsal plates of the disk, I may first of all state that 

 the two figures published by Lyman in 1878 and 1882 are not perfectly 

 in accord. In the first figure ('78, fig. 183) the dorsal plates of 

 the disk are all very small and almost equal, the primary plates 

 are distinct but also very small, and the radial shields are ex- 



