22 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



The specimen from station 5378 is of a general bright yellow 

 color; the dorsal surface of the disk is darker and greenish. The 

 other is a rather dark uniform brownish gray. 



The type series of this species was found by the Siboga among the 

 Sunda Islands at depths varying between 469 and 595 meters (255 

 and 322 fathoms). 



Although Ophiodera neglecta and Ophiomyxa irregularis belong 

 to two different genera, they show a very great external resemblance, 

 and as the latter is able to descend to a considerable depth it may be 

 met with in the same depth zones as the former. It is important, 

 therefore, to state accurately the characters which distinguish them. 

 The presence of a border of plates about the periphery of the disk 

 obviously establishes a generic differentiation, but as these plates 

 may be greatly obscured in alcoholic specimens it is very important 

 to search for them carefully. Characters peculiar to Ophiomyxa 

 irregularis by which this species may be distinguished from Ophio- 

 dera neglecta are the less-broadened mouth shields, the always- 

 rounded lateral mouth papillae, which are three in number, the four 

 strongly developed arm spines, the condition of the ventral arm 

 plates, which are in contact along a considerable portion of the arm, 

 and the stiffer appearance and lesser length of the arms. 



The distinction between the genera Ophiodera and Ophiomyxa 

 established by Verrill was not recognized by H. L. Clark in his 

 "Catalogue of Recent Ophiurans," published in 1915. Obviously the 

 character invoked by Verrill for the separation of the two has no 

 considerable significance, and the value that he attributes to it can 

 not be accepted ; however, that is purely a matter of personal opinion. 

 But it is certain that there can be distinguished in the genus Ophio- 

 myxa, taken in the broad sense in which it was used by Clark, species 

 provided with plates at the periphery of the disk and others which 

 do not have them ; each of these groups may be given the status of 

 a genus or of a subgenus. I have thought it best to adopt the nomen- 

 clature proposed by Verrill, which is the most convenient ; Matsumoto 

 has also accepted it in his memoir of 1917. 



NEOPLAX CRASSIPES, new species. 



Plate 2, figs. 1-3. 



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

 Oorregidor 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. E. 193, U.S.N.M.). 



Description. The diameter of the disk varies between 10 mm. and 

 11 mm. ; none of the arms is complete, the longest being preserved 



