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. ]\Iouth-papilloe closely soldered, forming a straiglit 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-enteriiigly curved, and a short blunt angle within ; second, 

 third, and fourth plates broader than long, much 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 almost the entire 

 covering of arm ; the second pair are very wide below, flattened and 

 flaring, a:nd form a part of the disk margin. Upper arm-plates small, broatler 

 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, microscopically 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. Eadial 

 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 minutie 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 

 Avithout 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 each 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 

 ot the star- fishes. It is an aberrant species, yet is correctly included by Sir 

 Wyville Thomson under Ophiomusium. Its distribution is wide, ami embraces 

 the South Atlantic, including the Cape of Good Hope ; and in de])th 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. 



