NO. 2 ZIESENHENNE: NEW OPHIURANS 21 



Ophiophragmus stellatus, new species 

 Plate 6, Figs. 6-9 



Description. — Disk diameter, 5.5 mm. ; arms, about 65 mm. long. 

 Disk flat and pentagonal, covered by numerous overlapping scales in an 

 irregular rosette. Conspicuously placed are the large circular central and 

 radial plates and one or two large oval plates in each interradius. The 

 plates are surrounded by numerous irregular disk scales. About 10 rows 

 of scales in each interradius, median row of scales the largest. Disk mar- 

 gin bears 15 to 18 long, well-spaced, cylindrical papillae, about 4 times 

 their diameter in length. Radial shields large, nearly half the disk radius, 

 longer than broad, acutely pointed within, separated within by 3 or 4 

 ovate scales. 



Upper arm plates oval, twice as wide as long, proximal and distal 

 margins broadly convex, lateral margins acutely convex, in contact with 

 each other. Side arm plates narrow, separated by a naked membrane, not 

 in contact above or below. Spine ridge prominent, bearing 3 heavy, flat- 

 tened arm spines, about an arm segment in length, uppermost shortest, 

 undermost heaviest and longest. 



Oral shields diamond shaped, slightly longer than wide, outer margins 

 concave. Madreporite swollen and considerably larger than other oral 

 shields. Adoral plates triangular, outer margin widest, not meeting 

 within. Jaws small and triangular. Three oral papillae on a side, outer- 

 most triangular, broad and flat; median spiniform, more than twice as 

 long as broad, longer than other papillae, resembling the fence papillae 

 more than an oral papilla; inner papillae blocklike, longer than broad, 

 separated from each other. Four broad, blunt teeth, uppermost longest. 



Interbrachial spaces below covered with small, uniform, overlapping 

 scales. Genital slits large and wide. Genital ridge covered with a series 

 of large, overlapping scales. 



First under arm plate small, proximal margin concave, other margins 

 straight. Second and succeeding under arm plates pentagonal, wider than 

 long, proximal lateral and distal margins concave, lateral margins 

 straight, plates in contact with each other. Two small, oval tentacle 

 scales placed at right angles to each other, inner scales slightly the longer. 



Color. — Dried from alcohol, upper surface pale gray, disk plates 

 slightly darker. Under surface light cream with some pale gray markings 

 on under arm plates. 



Types. — Holotype, AHF no. 17; 138 paratypes, 71 in M.C.Z. 



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