MUSEUM OF COMPARATIVE ZOOLOGY. 259 



This large and beautiful species has some relation to Ophiocamax in the 

 cluster of tooth-papillae at the end of the mouth-angle. 

 Station 148, St. Kitts, 208 fathoms, 1 specimen. 



Ophiacantha laevipellis sp. nov. 



Plate VI. Figs. 82-84. 



Special Marks. — Disk naked, or with a few scattered grains. Side arm- 

 plates meeting above and below. Seven or eight slightly thorny slender arm- 

 spines. 



Description of an Individual. — Diameter of disk 4.5 mm. Length of arm 

 about 18 mm. Width of arm, without spines, 1.5 mm. Mouth-angles long 

 and wide, and bearing on each side three spine-like, widely spaced papillae, 

 while the apex is occupied by the lowest tooth, which, like the four above it, 

 is of a blunt spear-head shape. The first under arm-plate also carries on its 

 inner edge two scale-like papilla?. Mouth-shields small, of a tranverse dia- 

 mond-form with rounded corners; length to breadth, .7 : .5. Side mouth-shields 

 wide and large, of almost a crescent shape, meeting broadly within. First 

 under arm-plate rounded hexagonal and nearly as large as a mouth-shield; 

 those beyond are widely separated by the side arm-plates, and are more than 

 twice as wide as long, with a curve without and a small peak within. Side 

 arm-plates meeting widely above and below, and forming a strong spine-ridge, 

 which, farther out, becomes so exaggerated as to give the arm a knotted look. 

 Upper arm-plates, beyond the first, of a blunt wedge form, with the point in- 

 ward. Disk covered with small imbricated scales which are quite naked (in 

 some specimens there are scattered grains). Radial shields pear-seed shaped ; 

 length to breadth, .5 : .4. Genital openings large, and extending from the 

 mouth-shield to nearly the margin of disk. Seven or eight glassy, flattened. 

 slightly thorny arm-spines, of which the uppermost is two or two and a half 

 times as long as a joint ; from this they grow shorter to the lowest spine, 

 which is no longer than one joint. The uppermost spines on top of arm 

 stand close to each other, on either side of the median line. One small, 

 pointed tentacle-scale. Color in alcohol, pale brown. 



Station 232, St. Vincent, 88 fathoms, 12-(- specimens. 



The figure of the upper surface is drawn from specimens of two varieties, 

 a smooth and a granulated. The former is the more common. This species 

 has some resemblance to O. serrata, but has narrower side mouth-shields and 

 much less thorny arm-spines. 



Ophiacantha scolopendrica sp. nov. 



Plate VI. Figs. 85-87. 



Special Marks. — Seven smooth arm-spines, of which the three Lowed arc 



much the smallest. Disk with a few scattered smooth grains, and small 

 rounded radial shields. 



