I\IUSEUM OF COMPARATIVE ZOOLOGY. 269 



shields narrow within and not quite meeting, while without they spread 

 inward to tlie tirst under arm-plate, and upward round the corner of the 

 mouth-shield to the head of the genital opening. Under arm-plates small, 

 about as broad as long; shield-shaped with a feeble angle inward; length to 

 breadth, 1.2 : 1.2. Side arm-plates Hat with an ill-marked spine-crest at their 

 outer margin; they meet below, but not above. Upper arm-plates wider than 

 long, hexagonal with outer and inner angles rounded, and lateral angles sharp. 

 Disk rather thick and covered by a tough skin, which exhibits obscurely belnw 

 a fine scaling, and above a few very minute, scattered spines. Over each side 

 of the arms is a swelling which looks like a radial shield, but is really the head 

 of the large genital plate, the small radial shield being wholly hidden under 

 the skin. Genital openings large, and extending from month-shield to margin 

 of disk. Five slender, delicate, tapering, rounded hollow arm-spines. No 

 tentacle-scales outside the mouth. Color in alcohol, disk greenish; arms pale 

 brown. 



Station 308, 41° 24' 45" N., 65° 35' 30" W., 1242 fathoms, 1 specimen. 



Ophiosciasma granulatum sp. nov. 



Plate VII. Figs. 99-103. 



Special Marls. — IMinute papilhc on edges of mouth-angles. Arms flat and 

 rather wide. Two flat, translucent arm-spines with rough edges. 



Description of an Individual. — Diameter of disk mm. Arms very low 

 and flat; width near disk 1.2 mm. ]\Iuuth-augle.s rather large, and liearing on 

 their edges a row of minute saw-like papillae; the two or three at the apex are 

 somewhat larger. Mouth-shields small and rounded, with a slight angle in- 

 ward; length to breadth, .7 : .7. Side month-shields wide and fully meeting 

 within. Under arm-plates rather thick, longer than broad, wider without 

 than within, and with deep re-entering curves on the sides, where are the 

 tentacle-pores. Side arm-plates ]n-ojecting in a strong s]iine-ridge, meeting 

 neither above nor liclow. The upper surface, covered oidy by a thin skin, 

 shows distinctly the tops of the elongated arm-bones with the pairs of circular 

 muscle-fields between them. Farther.,out on the arm there appears a central 

 depression, which towards the end penetrates ([uite through, until, at the tip, 

 the bone appears as two lung slender pieces curving towai'ds uncli other, and 

 uniting at either extrrniity. Disk covered with skin having si>attcred grains 

 on its surface, which are oparpie white. No scales or radial shiehls are visilde. 

 Two translucent rough arm-spinos, a little longer than a joint, and standing at 

 a strong angle to the arm. They are com]U)sed of two flattened s]u'cules sol- 

 den^l tdgrthcr, each of which has two or three spurs on its free edge (Fig. 101), 

 and are enclosed in a skin-bag. Tentacles simple, fleshy, and very thick. No 

 tentacle-.scale.s. Color in alcohol, pale yellowish, with yellow tentacles. 



A larger specimen with a disk of 10 nun. had arms 45 mm. long; but did 

 not dilfer excrpt in h.iving many of the di.-k granule., buried in the thick skin. 



