NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 173 



and rounded ; just back of the apical papilla is the small pointed scale 

 of the first oral tentacle pore, which might very naturally be counted 

 as a fifth oral papilla. Genital slits very large. First under arm 

 plate very small, rounded ; succeeding plates squarish or a little longer 

 than wide, in contact at least on basal part of arm. Side arm plates 

 moderate, meeting above and below very little or not at all; each one 

 carries five slender, sharp spines, of which the lowest is longest and 

 exceeds the joint. Tentacle scales two, not at all spiniform. Color 

 (dried from alcohol), very light brownish, the disk more or less gray. 



Locality. Albatross station 3131, off California, lat. 36 41' 30" N.; 

 long. 121 54' 10" W., 48 fathoms, brown mud, rocks, bottom tem- 

 perature 50.8, 40 specimens. 



Type. Cat. No. 25614, U.S.N.M., from station 3131. 



This species appears, from its mouth parts, radial shields, and 

 spiny disk to be entitled to a place in Amphilimna, but the small 

 number of arm spines and the flat, rounded tentacle scales have made 

 me hesitate to place it there. The specimens show little diversity in 

 size or color. The characteristic disk covering of Ophiocnida com- 

 bines with the five arm spines, the nearly circular oral shields, and 

 the mouth parts of an AmpJiioplus to make this an easy species to 



recognize. 



OPHIONEREIS EURYBRACHIPLAX, new species.o 



Disk 24 mm. in diameter; arms about 160 mm. long, probably. 

 Disk covered with a firm coat of minute, overlapping scales, which are 

 coarsest near the radial shields; there are about fifteen scales to the 

 square millimeter at center of disk. Radial shields very small and 

 widely separated, rather more than twice as long as wide. Upper 

 arm plates hexagonal, very wide, twice as wide as long or more, 

 broadly in contact ; supplementary pieces small, longer than wide, either 

 triangular with outer side very convex or tetragonal with outer distal 

 corner obliterated. Interbrachial spaces below covered with a coat 

 of very fine scales. Oral shield triangular, longer than broad (in the 

 Japanese specimen, fig. 78&, the breadth exceeds the length). Adoral 

 plates small, at sides of oral shields, wide distally but pointed at inner 

 end. Oral papilhe four or five on a side, truncate or blunt, the next 

 to the outermost the widest. Genital slits small. First under arm 

 plate squarish; succeeding plates tetragonal, with slightly curved 

 sides and rounded angles, at first wider than long, but becoming 

 sooner or later longer than wide, broadly in contact. Side arm plates 

 small, not nearly meeting either above or below ; each plate carries at 

 first four, then three, stout blunt arm spines, rather exceeding the 

 joint; basally the lowest is the longest but farther out the middle one 



" Et>puc, signifying vide, and ftpai'iwu, signifying arm, and -Aac, signifying plate, in 

 reference to the characteristic upper arm plates. 



