68 NATURAL HISTORY BULLETIN. 



Plate II; Figures 4, <\a. 



Arms very long and slender. Disk five-lobed, the lobes 

 extending out a little on the base of the arms. Teeth three 

 or four, upper one stout, spiniform, the others thicker, sub- 

 truncate. 



Mouth-papillae about five, partly slender, sub-spiniform, 

 rough at tip, irregularly crowded in a row, nearly equal in 

 length, but some are flattened and obtuse at tip.* Sometimes 

 there is also a somewhat stouter tooth-papilla. Within 

 mouth-slits, on each side, there are two (sometimes only one) 

 slender papillae, between the two oral tentacle-pores. 



Oral-shields exposed when dry, small, transversely ellip- 

 tical; adoral shields rather small, irregularly three or four- 

 lobed, not meeting proximally, where there is a patch of 

 naked cuticle between them, but distally separating the oral 

 shields from the side arm-plates. 



Genital slits wide and open near the oral shields, but nar- 

 row distally and not extending to the edge of the disk, bor- 

 dered by narrow, naked scales. 



» 



Under arm-plates small, but somewhat thickened, angu- 

 larly heart-shaped, with a deep distal notch or emargination, 

 the outer corners angular. They are separated by the sunk- 

 en side-plates, which leave central pits or indentations. No 

 tentacle-scale. The pores are small and round. Arm-spines 

 three or four, divaricate, small, very sharp, rough and glassy, 

 nearly equal, more or less webbed together and covered by 

 cuticle when in alcohol. They keep the same character to 

 the ends of the arms, where there are but two, borne on 

 prominent lobes of the side-plates. 



Upper arm-plates lacking. The internal arm-plates show 

 as transversely rhombic plates separated by wider intervals. 



*The irregularity of the papillae may be due to some former injury 

 and only partial restoration of these parts. Many of the papillae lack 

 the serrulate distal end, characteristic of the genus, and plainly seen 

 in the other specimens described below. 



