MUSEUM OF COMPARATIVE ZOOLOGY. 269 



shielJs narrow -within and not qnite meeting, Avbile without they spread 

 inward to tlio first nnder arm-plute, and upward round the corner of tlie 

 mouth-shiehl to tlie 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. Ujjper 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 below 

 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 

 ot" the large genital plate, the small radial shield being AvhoUy hidden under 

 the skin. Genital openings large, and extending from mouth-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. 99-102. 



Special Marls. — ]\Iinute papilhc on edges of mouth-angles. Arms flat and 

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



Description of an Individuul. — Diameter of disk 6 mm. Arms very low 

 and flat; width near disk 1.2 mm. I\Iuuth-angles rather large, and bearing 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 mouth-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 projecting in a strong spine-ridge, meeting 

 neither above nor below. The upper surface, covered only 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 quite through, until, at the tip, 

 the bone appears as two long slender pieces curving towards each other, and 

 uniting at either extremity. Disk covered with skin having scattered grains 

 on its surface, which are opaque white. Xo scales or radial shields are visible. 

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

 a strong angle to the arm. They are composed of two flattened spicules sol- 

 dered together, each of which has two or three spurs on its free edge (Fig. 101), 

 and are enclosed in a skin-liag. Tentacles sini])le, fleshy, and very thick. No 

 tentacle-scales. Colnr in alroliol, jiale yellowisli, willi yellow tentacles. 



A larger specimen with a disk of ID nun. liad arms 45 mm. Imig: but did 

 not dilTer except in having many of the di.-^k granule.:) buried in the thick skin. 



