MUSEUM OF COMPARATIVE ZOOLOGY. 151 



long, broader without than within, separated by transverse depressions ; outer 

 edge much thickened and curk^d downwards. Near end of arm they are wide 

 pentagonal, with an angle inward and the outer 'edge scarcely thickened. Side 

 arm-plates slightly projecting near base of arm ; meeting narrowly below, and 

 scarcely or not at all above. Upper arm-plates wider than long, irregular 

 in shape, with a curved outer side and an obtuse or irregular angle inward ; 

 length to breadth about 1.5 : 3.5. Disk (in alcohol) thick, rising well above 

 the arms, and with a deep constriction and furrow in each interbrachial space. 

 Along the outer portion of the interbrachial edge of each radial shield lie three 

 or four plates, broader than long, and running diagonally outward ; the rest 

 of the disk is occupied by coarse, irregular, overlappmg scales, beset with short, 

 stout, blunt, smooth, conical spines, which form an irregular line over the base 

 of each arm. Radial shields sunken, much longer than broad, narrowest within, 

 rounded and swollen without ; length to breadth 5:2; separated by one or 

 more narrow scales. Five stout, cylindrical, rather short arm-spines, tapering 

 to a blunt point, with thorns on all sides ; lengths to that of an arm-joint 3.7, 

 4, 3.7, 3, 2.5 : 2. Two thirds out on the arm, the second spine is much longer 

 and attains a length of 8 mm. Tentacle-scales very stout, and thickened at the 

 base ; pointed at the tip. On each of the first pair of pores there usually are 

 three, on the rest only one. Towards tip of arm the scale becomes spiniform. 

 Color in alcohol, pale brown. 



Station 205, 1050 fothoms. 



Smaller specimens (Station 214, PI. IX. Figs. 233-35) presented considerable 

 variations : with a disk of 10 mm. the arm was 60 mm. long ; there were only 

 seven mouth-papillae to each angle ; the disk-spines were thorny, the upper 

 arm-plates narrow ; the outer edge of the under arm-plates was somewhat 

 swollen, but not curled down ; the fii'st tentacle-pore had only one or two 

 scales ; there w^ere six comparatively long arm-spines, whose lengths to that 

 of an arm-joint were 5.2, 3, 2.8, 1.8, 1.8, 1.5 : 1.3. Other specimens (Sta- 

 tion 170), with disks from 12 mm. to 9 mm. in diameter, had smooth disk- 

 spines, like 205, and six arm-spines, and upper and under arm-plates, like 

 214. The number of mouth-papUloo to each angle varied from seven to ten, 

 without reference to size of specimen. 



Station 170, 630 fathoms, 6 specimens. Station 205, 1050 fathoms, 1 speci- 

 men. Station 214, 500 fathoms, 3 specimens. 



Ophiomitra Sarsii sp. nov. 



Plate VIII. Figs. 216, 217. 



Special Marks. — Eight stout cylindrical arm-spines. Tentacle-scales flat, 

 tapering, jagged. Scaling of disk finer than in 0. ■plicata. 



Descriptionofan Individual {Station 146). — Diameter of disk 15 mm. Length 

 of arm about 100 mm. Width of arm without spines 4.5 mm. Seven or eiglit 

 thick pointed mouth-papillae to each angle. Seven teeth of similar form, but 



