BULLFTIN OF THE 
OPHIOMASTUS * gen. ۰ 
Disk arched and extremely high, covered with a few large thick plates, 
among which the primaries are conspicuous for superior size. Arms short, with 
large thick side arm-plates. First under arm-plate similar to and nearly as 
large as those beyond. Mouth-papillee arranged in a narrow close-set line و‎ 
teeth rather slender; no tooth-papille. Small smooth arm-spines arranged 
along outer edge of side arm-plates, Two narrow genital openings in each in- 
terbrachial space. 
Ophiomastus tegulitius sp. nov. 
Plate VI. Figs. 167 -169. 
Special Marks. — Two very short, stout arm-spines. Disk-plates swollen 
and microscopically tuberculous. Side mouth-shield of a pointed ovoid shape. 
Description of an Individual (Station 165). — Diameter of disk 4 mm. 
Length of: arm about 6 mm. Width of arm close to disk, without spines, 
1mm. Mouth-papille so closely soldered as to form an almost continuous 
narrow line from side mouth-shields to apex ; on either side is a long curved 
one, followed by two shorter, and by a narrow spine-like one at apex of angle. 
Mouth-shield pentagonal, with an angle inward, longer than wide ; inner lat- 
eral sides straight, outer lateral corners rounded ; length to breadth ۰ 
Side mouth-shields large, swollen ; broadest and rounded within, where they 
meet, then tapering outward along the inner lateral sides of the mouth-shields. 
Under arm-plates long pentagonal, with an angle inward, lateral sides re- 
enteringly curved, outer side slightly curved, Side arm-plates large, thick, 
and swollen, meeting below and above ; upper arm-plates small, first one dia- 
mond-shaped, and second triangular with sharp angle inward and outer edge 
straight ; the rest are similar, but grow rapidly smaller. Disk highly arched and 
rounded ; in the centre a large hexagonal primary plate, surrounded by six oth- 
ers, much swollen, with inner and lateral sides nearly straight and outer edges 
rounded ; these seven plates cover almost the entire upper surface of the disk ; 
in the upper interbrachial space there is a rounded, much swollen marginal 
plate, and over the arm two small, joined, scale-like radial shields, On the 
under surface, outside the mouth-shield, there are two large plates, the outer 
and larger one connecting with the large marginal plate. Genital scale long and 
wide, and composed of three pieces. Tentacle-scales long, narrow, and curved, 
the one on the interbrachial side being semicircular, while the other on the lat- 
eral side of the under arm-plate is small and lip-like. Two very short, blunt 
arm-spines, placed low on the outer edge of the side arm-plate. Color in alco- 
hol, pale straw. 
A smaller specimen, with a disk of 2 mm., showed no special variations, ex- 
cept that the radial shields were relatively larger and there were only six pri- 
mary plates, which is doubtless the normal number. 
* Bois, a snake : paorós, a breast. 
