NO. 2 ziesenhenne: newophiurans 29 



Ophiochitonidae 



Genus OPHIONEREIS Lutken 



Ophionereis dictyota, new species 

 Plate 6, Figs. 1-5 



Description. — Disk diameter, 9 mm. ; arms broken, longest about 67 

 mm. long. Disk covered with thick and overlapping scales which become 

 thicker surrounding the radial shields. Extending interradially from the 

 radial shields, at the margin of the disk, is a series of 6 to 8 large, distinct 

 scales, about Yz as long as the length of the radial shields. Radial shields 

 small and pennantlike, about 3 times as long as broad, proximally finely 

 pointed, distally rounded, surrounded by large disk scales. 



First upper arm plate small, oval, proximal margin concave, distal 

 convex. Second plate hexagonal, twice as large as the first; third and suc- 

 ceeding plates larger. The plates are hexagonal, broader than long, fully 

 in contact. Proximal and proximal lateral margins concave, distal lateral 

 margins convex, distal margin nearly straight. Supplementaiy plates 

 longer than wide, inner margin concave, outer margins convex to form a 

 distinct, rounded, outer distal angle. Side arm plates separated from 

 each other by a soft membrane. Each plate bears 3 rounded, tapering and 

 slightly curved, blunt-tipped arm spines, slightly longer than an arm 

 segment, the median longest. Upper spine flat, blunt and little curved. 



Oral shields oval, longer than wide, proximally convex, distal lateral 

 margins concave. Adoral plates lanceolate, wider than long, enlarging 

 distally with a rounded margin, not meeting within. Jaws long and nar- 

 row. Four or 5 oral papillae on a side, outermost flat and triangular; 

 others blunt and angular, almost rounded ; apical smallest, shorter than 

 others. Four broad and rounded teeth, lowermost shortest and thick, 

 uppermost thin and long. 



Interbrachial spaces below densely covered with fine overlapping 

 scales. Genital slit ridge bears numerous fine stumps, longer than broad 

 proximally, becoming shorter and fewer distally. First under arm plate 

 quadrangular, proximal margin narrow and concave, lateral margins 

 almost straight, and distal margin decidedly rounded. Second plate much 

 larger, square, proximal margin little concave, plates only ^ in contact, 

 distally even less so. One large, oval, flat tentacle scale, almost ^ the 

 length of under arm plate. 



Color. — Dried specimens had a cream-colored disk, reticulated with 

 brown markings which continue to the oral shields. Proximally between 



