24 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 



the side arm plates, radial shields in contact distally, oral shields diamond 

 shaped, granulations on the genital ridge instead of scales with parallel 

 furrows, and triangular-oval upper arm plates little wider than long. The 

 name laevis has reference to the very smooth disk. 



Genus AMPHIODIA Verrill 



Amphiodia sculptilis, new species 

 Plate 5, Figs. 1-3 



Description. — Disk diameter, 5.5 mm.; arms, 26 mm. long. Disk 

 round and thick, covered with numerous plates. A small pentagonal cen- 

 tral plate and 5 narrow radiating plates form a star on the disk. Between 

 the narrow plates are 5 larger radial plates about the size of the central 

 disk plate. In each interbrachial area are 7 series of long plates, the middle 

 series broadest and overlapping the other series. Numerous small, overlap- 

 ping scales radiate out from the center of the disk. Radial shields rounded 

 triangular, longer than broad, outer and distal margins convex. A small 

 triangular scale separates the shields within, and in some cases smaller 

 elongated plates may separate them. The radial shields in all specimens 

 are separated within by at least one triangular scale; without they are in 

 contact. Sides of disk covered with overlapping scales. Lateral to the geni- 

 tal plate and distal to the radial shield is a series of 3 or 4 minute, blunt, 

 cylindrical spines. 



Upper arm plates rectangular, almost twice as broad as long, fully in 

 contact with each other, margins straight, distal angles slightly rounded. 

 Side arm plates small, arm spine ridge prominent, bearing 3 short, broad, 

 bluntly rounded arm spines, uppermost slightly largest. 



Oral shields very small and diamond shaped, an obtuse angle within 

 and truncated without. Adoral plates triangular, broader than long, 

 widest distally, proximal margins concave, the combination of all the 

 adoral plates and oral shields gives the under side a star-shaped appear- 

 ance; within each raylike depression the mouth papillae are located. Jaws 

 small and narrow, bearing 3 oral papillae on a side, outermost largest, 

 flat and triangular; median oval, slightly smaller than others; proximal 

 oblong, twice as long as wide, blocklike, and separated from each other. 

 Five broad teeth, uppermost longest. 



Interbrachial spaces below covered with uniform overlapping scales 

 that are continuous with the interbrachial scales. Genital slits narrow, 

 bordered by a series of uniform overlapping scales. First under arm plate 

 small, triangular, broader than long. Second and succeeding plates larger, 



