182 BULLETIN 75, UNITED STATES NATIONAL MUSEUM. 



somewhat pentagonal, with a i)roxiinal anu;le and a straio;ht distal 

 margin. Side arm plates very large, meeting broadly both above and 

 below; each plate carries four slender, pointed spines, but on the first 

 joint beyond the disk, each side arm plate carries eight and on the 

 second joint seven such spines; these sixteen and fourteen spines, 

 respectively, nearly encircle the arm, except on the lower side; the 

 uppermost spine is the longest and smoothest and may equal two 

 joints; the lowest is shortest and roughest and is only about half as 

 long as a joint, except on the first two or three. Tentacle scale single, 

 oval, rather small. Color (dried from alcohol), very light gray, nearly 

 white. 



Localities.— Albatross station 4908, Eastern Sea, lat. 31° 40' N.; 

 long. 129° 29' 40" E., 434 fathoms, gray globigerina ooze, bottom 

 temperature 42.9°, 1 specimen; station 4957, Bungo Channel, Japan, 

 lat. 32° 36' N.; long. 132° 23' E., 437 fathoms, green-brown mud, 

 fine gray sand, foraminifera, bottom temperature, 39.8°, 2 specimens. 



Ty pi.— Cat. No. 25637, U.S.N.M., from station 4908. 



The short, closely joined radial shields, the small widely separated 

 upper arm plates, the encircling rows of arm spines at base of arms 

 and the huge adoral plates combine to give this species an unique 

 appearance. It can hardly be confused with any other species, except 

 possibly the following. 



OPHIOMITRA HABROTATA, new species.a 



Disk 3^ mm. in diameter; arms ver.y slender, about 28 mm. long. 

 Disk nearly circular, covered by about one hundred and fifty rather 

 irregular, coarse scales, many of wdiich bear each a single small, blunt 

 spinelet, while a few at the center of the disk carry each a long, sharp 

 spine. Radial shields very large, somewhat triangular, nearly twice 

 as wide as long, in contact only at distal end, where one of the pair 

 may carry a long, sharp spine. Upper arm plates somewhat trian- 

 gular, wider than long, with a convex distal margin, smooth and 

 shining, slightly swollen, and widely separated from each other. Be- 

 tween the upper arm plates, the arms are much constricted, so that 

 they have a beaded appearance. Interbrachial spaces below, wide, 

 covered by numerous rather coarse scales. Genital slits very small and 

 inconspicuous. Oral shield very small, somewhat triangular, longer 

 than broad. Adoral plates relatively huge, much wider without than 

 within, where they meet; oral plates very small. Oral papilla^ three 

 or four on a side and one at apex of jaw; outermost very wide with a 

 straight margin, the others narrow and pointed. First imder arm 

 plate hexagonal, longer than wide; succeeding plates about as long as 

 wide or longer, pentagonal or squarish, widely separated from each 



a 'A0p6c, signifying delicate, dainty, in reference to its light and delicate structure. 



