NOKTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 27 



55.9°, 2 specimens; station 4894, Eastern Sea, lat. 32° 33' N.; long. 

 128° 32' 10" E., 95 fathoms, gray sand, broken shells, pebbles, 1 

 specimen; station 4895, Eastern Sea, lat. 32° 33' 10" N.; long. 128° 

 32' 10" E., 95 fathoms, gray sand, broken shells, pebbles, 2 speci- 

 mens. Bathymetrical range, 44 to 106 fathoms. Seven specimens 



Type.— Cat. No. 25600, U.S.N.M., from station 3764. 



Although this species is obviously related to 0. infernalis, it differs 

 so markedly in two important particulars that I have no doubt it is 

 entirely distinct, and there is no other species with which it can be 

 confused. In the first place, the granulation of the disk is nearly 

 twice as fine in infernalis as in megalaspis, there being 400 to 500 

 granules to the square millimeter in the former. This difference in 

 the size and number of the granules results in a noticeable differ- 

 ence in the apparent smoothness of the disk in dry specimens. The 

 second, and much more noticeable, character in which the two species 

 differ is found in the radial shields; in infernalis they are small, often 

 no larger than one of the other bare disk plates, and never larger than 

 an upper arm plate, while the distance between the two of a pair 

 greatly exceeds the width of the plate. The contrast between these 

 proportions and those shown by megalaspis is thus very striking. 



OPHIOCONIS DIASTATA, new species." 



Disk 9 mm. in diameter; arms about 45 mm. long. Disk covered 

 with a close fine coat of granules, about 130 to the square millimeter 

 at center of disk. Radial shields entirely covered. Upper arm plates 

 triangular, much wider than long, even the basal ones scarcely in con- 

 tact. Interbrachial spaces below finely granulated like the disk above. 

 Oral shields wider than long, with rounded sides and a blunt proxi- 

 mal angle. Adoral plates rather small, narrowest proximally, with 

 outer end more or less concealed by an extension of granulation 

 of interbrachial space, and with tip of inner end often concealed by a 

 coarser granulation which completely conceals the oral plates. Oral 

 papillse four or five on each side, the outermost much the widest; an 

 infradental papilla sometimes present but often wanting; teeth, three 

 or four, moderately wide, rather blunt. First under arm plate, not 

 half as large as second, narrower distally; succeeding plates much 

 wider than long, more or less pentagonal, with a wide proximal angle. 

 Side arm plates large, meeting above and still more broadly below; 

 each carries four or five flat, smooth, hollow, not very acute arm 

 spines; next to uppermost longest, somewhat exceeding joint. Ten- 

 tacle scale single, large, longer than wide, rounded or sometimes 

 bluntly pointed. Color (dried from alcohol), nearly white. 



o Jioa-aroc, signifying separated in reference to the widely separated under arm 

 plates. 



