MUSEUM OF COMPARATIVE ZOOLOGY. 95 



slight re-entering cun-e ; interbrachial edges curved ; length to breadth 1.5 : 

 1.3. Interbrachial space below filled by a large slightly swollen plate, which 

 is sometimes divided in two by a median line, and by the large, thick, longer 

 than broad genital scales, along the free edge of which are eight or more very 

 minute, short, blunt papillae, extending to upper margin of disk, where they 

 bear an arm-comb of two or three papilla). Three short delicate arm-spines 

 about two thirds the length of a joint, two low on the under surface of the arm, 

 and one well up on its side. Tentacle-scales on the first set of pores, two on 

 the interbrachial side and one on the brachial ; beyond this there is only one 

 large scale on the inner side. Color in alcohol, white. 



The proportionate size of the side arm-plates and small number of those of 

 the disk show this to be a young specimen, but its characters are so well 

 marked as to warrant a description, and its great depth gives it importance. 



Station 158, 1800 fathoms, 1 specimen. 



[ Ophioglypha inermia sp. nov. 



Plate V. Figs. 133-135. 



Special Marks. — Xo arm-comb, and only a feeble row of grains along the 

 genital opening. Disk covered with thin overlapping scales and very small 

 radial shields. 



Description of an Individual (off Tristan d'Acunha). — Diameter of disk 

 14 mm. Length of arm about 70 mm. Width of arm close to disk, without 

 spines, 2.5 mm. Mouth-papillce small, short, pointed, and close-set, similar to 

 and continuous with the tentacle-scales of the second pair of mouth-tentacles. 

 If true mouth-papilloe be those that stand on the mouth-frames, there are eight 

 or ten on either side and a cluster of three somewhat larger on the jaw-plate. 

 Mouth-shield broader than long, with very blunt angle inward and outer edge 

 curved ; length to breadth 2 : 2.7. Side mouth -shields longer than broad, of 

 nearly equal width, nearly or quite meeting within. First under arm-plate 

 small, longer than broad, hexagonal ; second plate broader than long, rounded 

 quadrangular ; beyond this the plates become much broader than long, with 

 sharp angles at the lateral sides, a small peak within, and a rounded angle 

 without.- Side arm-plates thin, not swollen, just meeting below beyond the 

 fourth under arm-plate ; separated above by the large upper arm-plate.s, which 

 are much broader than long, and wider without than within, with lateral sides 

 straight, and outer comers rounded. Disk high and round, covered above and 

 below with very thin, closely overlapping scjiles, with one minute circular pri- 

 mary plate in centre of disk. Radial shields small, nearly round, separated 

 by a large angular plate ; length to breadth 1.3 : 1. Genital scales hidden ; 

 along their free edge is a row of very minute, bead-like papilla) ; three slim, 

 flat, pointed, nearly equal arm-.spines, somewhat longer than an arm-joint, and 

 equally spaced along the outer edge of the sid'^ arm-plate. The first pair of 

 tentacle-pores, which open into the mouth-slit, have six or seven minute 

 tentacle-scales, exactly like the mouth-papilla), and arranged in an ox-bow 



