256 BULLETIN OF THE 



The genus is new to North European waters. The species differs from 

 Ophiochiton lentus, which comes from 600 fathoms, southeast of the Fijis, in 

 having three long slender arm-spines and only one tentacle-scale. 



Ophiacantha Bairdi sp. nov. 



Plate V. Figs. 70-72. 



Special Marks. — Disk closely and uniformly beset with elongated pointed 

 granules, among which appear a few short scattered spines. Seven or eight 

 slender, smooth, sharp arm-spines. Eleven mouth-papillye to each angle. 



Description of an Individual (Station 340). — Diameter of disk 9.5 mm. 

 Length of arm about 45 mm. Width of arm close to disk 2 mm. Eleven 

 papillae to each mouth-angle, whereof the outer one on each side is broad and 

 flat, with a rounded cutting edge, and the rest are much narrower and tooth- 

 like, including the odd one at the apex. Five broad flat teeth with a curved 

 cutting edge ; the uppermost one narrower than the others. Mouth-shields 

 small, of a broad oval, or transverse heart-shape ; length to breadth, .8 : 1.2. 

 Side mouth-shields rather large, growing suddenly wider at the outer end, 

 meeting within. Under arm-plates pentagonal, with an obtuse angle within, 

 lateral sides a little re-enteringly curved, and outer side widely curved. Upper 

 arm-plates diamond-shape with the angles much rounded. Side arm-plates 

 rather stout, nearly meeting above and below near base of arm. Near tip of 

 arm the side plates meet broadly above and below, and have only a feeble 

 spine-crest. The upper arm-plaies are there three-sided with an angle inward. 

 Disk slightly puffed ; closely and uniformly beset with elongated, pointed 

 grains, among which stand a few scattered short spines. No scaling or radial 

 shields visible. Seven or eight long, slender, pointed, not rough arm-spines. 

 The uppermost one is usually short ; then the next three are as long as two 

 or two and a half joints ; the four lowest not much longer than one joint. 

 One large, pointed, longer than broad tentacle-scale. Color in alcohol, nearly 

 white. 



Station 308, 41° 24' 45" N., 65° 35' 30" W., 1242 fathoms. Station 340, 

 39° 25' 30" N., 70° 58' 40" W., 1394 fathoms. 



The species is quite near 0. vepratica, from which it is distinguished by 

 having eleven itistead of seven mouth-papilla) to each angle, and by the elon- 

 gated, pointed grains of the disk. 



Ophiacantha Bartletti sp. nov. 



Plate V. Figs. 73-75. 



Special Marks. — Structure delicate, with narrow arms and four smooth, 

 slender arm-spines. A few scattered spines on disk, whose scaling above is 

 scarcely distinguishable. No tentacle-scales. 



Description of an Individual. — Diameter of disk 12 mm. Length of arm 

 about 75 mm. Width of arm 2 mm. Five spine-like, spaced mouth-papilla? 



