114 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



very close together in the median dorsal line of the arm, though the 

 two rows remain distinct on each side and are not continuous with 

 each other. The surface of the spines shows a few rugosities which 

 are very irregular and inconstant, but no denticulations properly 

 speaking. The length of the first ventral spine equals that of the 

 segment ; the last dorsal spine is as long as two segments. 



The tentacle scale of the pores of the first pair is single, rather 

 large, broadened, and almost circular; it becomes narrower on the 

 three or four following pairs, and then conical and rather pointed, 

 though always remaining short. 



Affinities and distinctive features. — Ophiomitrella sagittata is very 

 close to 0. mutata Kcehler, which it recalls in the armature of the 

 dorsal surface of the disk ; but the form of the mouth shields is very 

 different, and the elongation of the proximal angle prevents the two 

 adoral plates of each pair from touching each other in the median 

 interradial line; the upper arm plates have the distal border very 

 much less convex, the spines are more numerous and stouter, and, as 

 it seems to me, shorter than in 0. mutata. Although these differences 

 are not very important, I have not felt myself justified in uniting 

 the two species; perhaps the examination of more numerous speci- 

 mens will show intermediate forms, particularly in reference to the 

 outlines of the mouth shields ; but at present none are known. 



OPHIOMITRELLA SUBJECTA, new species. 



Plate 26, figs. 5-9; pi. 94, fig. 4. 



Localities. — Albatross station 5280; China Sea in the vicinity of 

 southern Luzon; Malavatuan Island (N.) bearing S. 60° W., 11.3 

 kilometers (6.1 miles) distant (lat. 13° 55' 20" N., long. 120° 25' 55" 

 E.) : 353 meters (193 fathoms) ; July 17, 1908; gy. S. 



Three specimens (Cat. No. 41287, U.S.N.M.). 



Albatross station 5300 ; China Sea in the vicinity of southern Luzon 

 (lat. 20° 31' N„ long. 115° 49' E.) ; 485 meters 265 fathoms); 

 August 8, 1908 ; gy. M., S. 



One small specimen (Cat. No. 41286, U.S.N.M.). 



Albatross station 5325; off northern Luzon; Hermanos Island (N.) 

 bearing N. 86° E., 31.04 kilometers (16.75 miles) distant (lat. 18° 34' 

 15" N., long. 121° 51' 15" E.) ; 410 meters (224 fathoms) ; November 

 12, 1908 ; gn. M. 



Two specimens (Cat. No. 41288, U.S.N.M.). 



Description. — In the largest specimen, which is one of the two 

 from station 5325, the diameter of the disk is 9 mm. ; the arms are 

 incomplete. The other specimens are a little smaller, and in one of 

 them, in which the disk is 8 mm. in diameter, the arms reach 40 mm. 

 in length. In the smaller from station 5325 the diameter of the 

 disk is only 5 mm. In the specimen from station 5300 the diameter 



