MUSEUM OF COMPARATIVE ZOOLOGY. 119 
Description of an Individual * (Station 122). — Diameter of disk 4.5 mm. 
Length of arm about 7 mm. Width of arm close to disk, without spines, 
1 mm. Mouth-papille closely soldered, forming a straight line on the sides, 
with one round, bluntly pointed papilla at apex of the jaw. Mouth-shields 
small, triangular, with a long angle within, outer edge much rounded ; length 
to breadth, .5 :.5. Side mouth-shields large, long, and narrow, meeting within, 
wider without than within, with outer ends rounded. First under arm-plate 
of a rude wedge-shape, having the outer edge widest, and curved, long lateral 
sides slightly re-enteringly curved, and a short blunt angle within ; second, 
third, and fourth plates broader than long, mach broader without than within, 
lateral sides with deep re-entering curve, and outer side strongly curved ; fifth 
plate triangular, and much smaller; beyond which the plates are diamond- 
shape and minute. Side arm-plates wide and swollen, meeting broadly above 
and below, beyond the sixth under arm-plate forming alimost the entire 
covering of arm; the second pair are very wide below, flattened and 
flaring, and form a part of the disk margin, Upper arm-plates small, broader 
than long, with outer edge gently and inner edge deeply curved ; growing 
rapidly smaller, and almost disappearing beyond the sixth. Disk thick and 
round, covered with swollen, mieroscopieally tuberculous plates ; in the centre 
are six primary plates, forming a regular rosette, the central one pentagonal, 
the others hexagonal, and each bearing a large tubercle ; in the interbrachial 
space there is one large square plate, also bearing a tubercle; outside this is a 
large, much swollen marginal plate, which is much wider without than within, 
the inner edge being straight and the outer re-enteringly curved. Radial 
shields large, rudely oval, longer than broad, joined for nearly their whole 
length ; overlapped on their inner ends by one of the primary plates, and 
separated without by a small, much swollen, semicircular plate ; length to 
breadth 1 :.7. On the lower interbrachial space there are two minute plates, 
just outside the mouth-shield ; then the two great genital scales, which occupy 
most of the space, and meet within at the mouth-shield, and are separated 
without by a large thick plate, wedged between them, which extends outward 
beyond the margin, in form of a tubercle. The first side arm-plate carries two 
short, thick, blunt arm-spines ; the second, which forms part of the margin of 
the disk, has three spines ; the rest have two, all situated low on the outer edge. 
One large, rounded tentacle-scale on the inner side of cach tentacle-pore of the 
first five under arm-plates, Color in alcohol, white. 
By its curious, flaring under arm-plates at the base of the arm, and its 
short, rapidly tapering arm, this species gets a fanciful resemblance to some 
of the star-fishes, It is an aberrant species, yet is correctly included by Sir 
Wyville Thomson under Ophiomusium. Its distribution is wide, and embraces 
the South Atlantic, including the Cape of Good Hope ; and in depth from 150 
to 1675 fathoms. 
Station 87. 1675 fathoms (Wyv. Thom.). Station 122, 350 fathoms, 4 speci- 
mens, Station 142, 150 fathoms, 3 specimens. 
* The description is from a specimen larger than the one figured, 
