MUSEUM OF COMPARATIVE ZOOLOGY, 95 
slight re-entering curve ; interbrachial edges curved ; length to breadth 1.5 : 
1.8. 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 papille, extending to upper margin of disk, where they 
bear an arm-comb of two or three papille. 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 inermis sp. nov. 
Plate V. Figs. 123-125. 
Special Marks. — No 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 
14mm. Length of arm about 70 mm. Width of arm close to disk, without 
spines, 2.5 mm. Mouth-papille small, short, pointed, and close-set, similar to 
and continuous with the tentacle-scales of the second pair of mouth-tentacles, 
If true mouth-papilla 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-plates, which 
&re much broader than long, and wider without than within, with lateral sides 
straight, and outer corners rounded. Disk high and round, covered above and 
below with very thin, closely overlapping scales, 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 و‎ 
along their free edge is a row of very minute, bead-like papillo ; three slim, 
flat, pointed, nearly equal arm-spines, somewhat longer than an arm-joint, and 
equally spaced along the outer edge of the side 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-papille, and arranged in an ox-bow 
