20 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



five in number. These differences are obviously rather slight, and 

 it is undeniable that the two forms are very closely related ; without 

 doubt they are corresponding types, one inhabiting the Indian Ocean 

 and the western Pacific, the other the American shores of the latter 

 ocean. 



On the basis of the figures given above, in connection with the list 

 of the Albatross stations at which this species was collected, it can 

 be stated that this form is able to live at quite different depths, rang- 

 ing between 36 and 581 meters (20 and 318 fathoms). The greatest 

 depth at which the Siboga found O. irregularis was only 141 meters 

 (81 fathoms). 



OPHIODERA NEGLECTA Koehler. 



Plate 6, figs 3, 7, 8. 



Ophiodera nsglecta Kcehlek, '04, p. 153, pi. 18, figs. 6, 7. 

 Ophiomyxa neglecta H. L. Clark, '15, p. 170. 



Localities. — Albatross station 5378 ; Marinduque Island and vicin- 

 ity; Mompog Island (E.) bearing N. 38° W., 31.50 kilometers (17 

 miles) distant (lat. 13° 17' 45" N., long. 122° 22' 00" E.) ; 722 

 meters (395 fathoms) ; March 4, 1909 ; sft. gn. M. 



One specimen (Cat. No. E. 330, U.S.N.M.). 



Albatross station 5510; Northern Mindanao and vicinity; Camp 

 Overton Light bearing S. 68° E., 16.86 kilometers (9.1 miles) dis- 

 tant (lat. 8° 16' 00" N., long. 124° 03' 50" E.) ; 744 meters (423 

 fathoms) ; August 7, 1909 ; gy. M., fne. S. 



One specimen. 



Notes. — In the specimen from station 5378 the two diameters of 

 the disk are 15 mm. and 17 mm. The arms are very long and nar- 

 row, their length exceeding 90 mm. ; they remain of the same width 

 almost throughout the proximal half, tapering more rapidly in the 

 distal. The specimen from station 5510 is a little smaller. 



I shall here include some notes supplementary to the original de- 

 scription published in 1904. It has seemed advisable also to include 

 three photographs of the specimen from station 5378, which I have 

 dried in order to render the outlines of the plates more readily 

 discernible than they are in alcoholic specimens. 



The radial shields are very evident in the dried specimen ; they are 

 broadened, rather short, twice, and some of them even three times, as 

 long as broad. There is not the slightest trace of plates on the 

 periphery of the disk, and the species certainly belongs to the genus 

 Ophiodera as that genus was diagnosed by Verrill. The dorsal sur- 

 face of the disk is covered by a slightly wrinkled integument, and 

 I notice here and there, principally between the radial shields, some 

 small calcareous nodules, which are rounded and few in number. 



