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H- ^ ■_ 



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176 



THE OPIIIURIDiE. 



with a little peak within and a rather broad lobe without. The corners are 

 very largely rounded^ inner and outer sides concave. Side mouth shields 

 very narrow in the middle, broader^ rounded at the inner end, where they 

 scarcely meet, broadest without. 



1 



First ventral plate almost as large as the rest, five-sided, with outer edge 

 straight. Those beyond all distinctly, but not widely separated ; they have 

 a little peak or very obtuse angle within, the inner laterals forming an 

 almost straight line across the arm ; sometimes the peak wholly disappears. 

 Outer edge rounded, with a little median cut, outer corners rounded, outer 

 laterals long, re-enteringly curved. The inner plates are about equally 

 broad and long, farther out they become considerably longer than broad. 

 Side arm-plates with spine-ridge little prominent; a naked space separating 

 those of each two adjoining joints rather distinct, also from the dorsal side. 

 Dorsal plates triangular, a little more broad than long, with outer edge 

 curved. On the inner 5 to 10 joints they have inner angle truncated, and 

 are separated by a naked space, which also separates the side arm-plates. 

 More or less of the inner dorsal plates are rudimentary, surrounded by 

 naked skin; sometimes they are quite irregular, divided in small pieces. 



Arms not knotted. 



Disk covered above and below by dehcate overlapping scales, which 

 bear some spread, simple, not thorny spines (Fig. 4), c. 0.5 mm. long. Some- 

 times also such spines are found on the inner arm-joints. The radial shields 

 are uncovered, small, narrow, mostly a little curved, much diverging within ; 

 they are wholly separated by several small scales. There seems to be a 

 rather thick skin covering the disk. Genital scales not distinct. 



4 to 5 short, smooth arm-spines, about as long as a joint, the upper one 

 a little longer. One very small, quite rudimentary, spine-like tentacle scale 

 at the inner end of the large pores. 



Color in alcohol : gray. * 



Stations 3361; 1471 f.3 3362, 1175 f . ; and 3414, 2232 f . ; one specimen 



from each. ^ 



This species is nearly related to O. Barlletti Lym., from which it is, 

 however, easily distinguished by its tentacle scales; 0. BartleUi has none. 

 Especially the remarkably formed ventral plates are alike in these two 



species. 



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