NO. 2 ZIESENHENNE : NEW OPHIURANS 37 



paratypes. A central plate is sometimes found, but a symmetrical rosette 

 has not been seen in the 17 specimens. In several specimens radial shields 

 and interradial plates are in contact with the central plate at one point. 

 Interbrachially is a large, transversely oval plate in contact with the inter- 

 radial plate and separated from the radial shields by one or 2 smaller 

 plates. Radial shields large, hexagonal, about half the disk radius, slightly 

 longer than wide, broadly in contact. 



First upper arm plate small, triangular, with the peak within, bearing 

 2 to 5 fine spinelets on each lateral margin along the genital slit. Second 

 plate hexagonal, swollen, broader than long, distal and proximal margins 

 straight, lateral margins little concave, bearing 4 to 8 fine spinelets along 

 the genital slit. Third plate hexagonal, about as long as broad, swollen, 

 with straight proximal and distal margins. Succeeding plates pentagonal, 

 then quadrangular, becoming triangular distally, longer than broad, lat- 

 eral margins straight, distal margins convex. Basal 8 plates in contact, 

 distally they become farther separated by the side arm plates until they 

 are reduced to ^ the length of an arm segment at the extremities. All 

 plates are finely granulated. First side arm plate greatly reduced, bearing 

 2 short, broad tentacle scales and 2 long, conical arm spines on the genital 

 slit. Third plate slightly larger, bearing 3 short, broad tentacle scales and 

 4 long, slender, pointed, well-spaced arm spines along the genital slit. 

 Fourth to 8th plate bearing 2 small, flat, long tentacle scales or modified 

 arm spines, succeeding plates bearing only one. Fourth and succeeding 

 plates bear 5 then 4 long, finely tapering, well-spaced arm spines, about 

 Yz the length of the arm segment, median spine longest, upper and lower- 

 most shortest. 



Oral shields large, occupying the interradius below, oval, longer than 

 wide, with an acute angle within and broad, convex lateral and distal 

 margins. Adoral plates quadrangular, little broader than long, meeting 

 within. Jaws wider than long, scarcely larger than adoral plates. Four 

 or 5 oral papillae on a side, outermost twice as broad as long; next broader 

 than long; next delicate, longer than broad, apical broad, heavy, pointed, 

 longer than broad. Three narrow pointed teeth, undermost shortest. 



Interbrachial spaces below covered by the large, oval oral shields and 

 2 or more small interbrachial plates. Genital slits long, extending from 

 the adoral plates to the radial shields. Genital plates long and narrow, in 

 contact with the distal margin of the radial shields; each plate bears a 

 comb of 18 to 26 fine, long, tapering, pointed spines, well separated at 

 their bases, lowermost becoming shorter and blunt. First under arm plate 



