NO. 2 ZIESENHENNE: NEWOPHIURANS 39 



The name irregularis has been chosen for this species because of the 

 irregular arrangement of the disk scales. 



Amphiophiura paucisquama, new species 

 Plate 8, Figs. 1-3 



Description. — Disk diameter, 7 mm.; thickness of disk, 3.5 mm.; 

 arms, 13 mm. long. Disk large, arms relatively short, tapering rapidly. 

 Disk covered with 21 very large pitted plates including the radial shields. 

 A large, swollen, pentagonal central plate is surrounded by 5 slightly 

 larger plates that are in contact with the single, large, interradial plate 

 and the radial shields. The interradial plate is pentagonal with the proxi- 

 mal margins concave, forming a peak, lateral and distal margins almost 

 straight. Viewed under an ordinary hand lens all plates are deeply pitted, 

 resembling the mesh on a golf ball. Radial shields much smaller than 

 disk plates, pentagonal, fully in contact, decidedly broader than long, 

 deeply pitted as other disk plates. 



First upper arm plate oval, broader than long, fully in contact with 

 the second arm plate and radial shields, lateral margins bear genital slit 

 papillae. Distally the plate bears an elevated transverse ridge which is 

 deeply pitted. Second plate oval, broader than long, with a high convex 

 surface, deeply pitted, in contact with the first upper arm plate. Third 

 plate oval, slightly broader than long and rather high, elevated to re- 

 semble a golf ball, deeply reticulated. Succeeding plates diamond shaped, 

 becoming smaller, flatter, and more widely separated by the side arm 

 plates distally. Side arm plates twice as broad as long, swollen, in contact 

 below from the 5th arm segment out and in contact above from the 3rd 

 segment out. Three short, peglike arm spines about Yz the length of the 

 side arm plates, widely separated, upper longest and heaviest, under short- 

 est. The arm plates are separated from each other or appear that way be- 

 cause of the prominent spine ridge. All plates are deeply pitted by an 

 irregular reticulation similar to that on golf balls. 



Oral shields large, triangular, truncated within and broadly convex 

 without, longer than wide, occupying the entire ventral interradius. Ad- 

 oral plates small, diamond shaped, fully in contact and separated from the 

 oral shield by a furrow. Jaws diamond shaped, twice as long as wide. Four 

 or 5 oral papillae on a side, outermost largest, rectangular, broader than 

 long; 2nd and 3rd outermost rectangular, only slightly broader than long. 

 Inner papillae ovate, pointed, flat, longer than broad. Three bluntly 

 rounded teeth. 



