MUSEUM OF COMPARATIVE ZOOLOGY. 200 



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

 inward to the first 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 flat 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 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 

 of the large genital plate, the small radial shield being wholly 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 graimlatum sp. nov. 



Plate VII. Figs. 99-102. 



Special Marks. — Minute papillae 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 G mm. Arms very low 

 and flat; width near disk 1.2 mm. Mouth-angles rather large, and bearing on 

 their edges a row of minute saw-like papilla); 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. No scales or radial shields are visible. 

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

 a strong angle to the arm. They are composed of two flattened Bpicul 

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

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

 tentacle-SCales. Color in alcohol, palfi yellowish, with yellow tentacles. 



A larger specimen with a disk of 10 mm. bad arms !"> mm, long: but <lid 

 not differ except in having many of the disk granules buried in the thick skin. 



