444 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM, [IStto. 



of radial shields not exposed. Arm-spiues very long, slender, nearly 

 smooth, eight or nine at base of arms, those next to the edge of disk 

 decidedly longer and forming an almost continuous band above. Ten- 

 tacle-scales rather wide, but with acute tips at base of arms, rapidly 

 becoming smaller and acute-lanceolate farther out. Mouth-shields 

 rather small, rounded externally, and not extending much on thfe inter- 

 brachial spaces, obtuse -angled on the inner side. Jaws broader and 

 more obtuse than in most species. Mouth-papillse rather slender, usu- 

 ally three or four on each side of a jaw, besides the median one; the 

 outer one is largest, broad and flat at base, rapidly narrowed toward 

 the acute end; the next two are more slender, spiniform, and acute; 

 sometimes au additional smaller one stands out of line, behind those in 

 the regular row. Color, light orange or buff. Diameter of disk of a 

 large example, 17"""' ; length of arms, 110™'". 



Oft' Martha's Vineyard, stations 2034 and 2105, in 1,346 to 1,395 fath- 

 oms, 1883. On Brisinga elegans V. 



Ophiacantha crassidens Verrill. 



Verrill, Amer. Jouni. Sci., February, 1885. 



Verrill, Eeport U. S. Fish Com. for 1883, p. 45, 1885. 



This large species is easily distinguished by its disk, covered with 

 small, conical, acute spines, and by the remarkably large, rough, and 

 thick mouth papilhB, which are crowded. The arm-spines are rather 

 short and blunt. The color is dark brown in alcohol. 



Station 2115, in 843 fathoms, off" Cape Hatteras, 1883 (No. 9370). 



Ophiacautha gracilis Verrill, sp. iiov. 



Verrill, Eeport U. S. Fish Com. for 1883, p. 46, 1885. 



A small, delicate species, with long, slender, attenuated arms. Disk 

 round and full, covered with relatively large, easily visible scales, each 

 of which bears a rather large and high columnar spinule, a little en- 

 larged at the summit and terminated by five, six or more, slender, 

 sharp, divergent points. Arm-spines, along most of the length of the 

 arm, four or five, short for the genus, being about half as long as an 

 arm -joint ; the small upper one is tapered ; the lower ones are stouter, 

 rough, blunt, and hooked at the end ; the lowest is largest and most 

 hooked ; on the two joints next to the disk the five spines are much 

 longer, very slender, tapered, acute ; the two ui)per ones twice as long 

 as an arm-joint. Tentacle- scale small, spiniform ; mouth-papilliB few, 

 about three on each side of a jaw, besides a larger, odd, terminal one ; 

 the lateral ones are small, spiniform ; the two outer ones stand a little 

 back from the slit, like tentacle-papillse ; mouth-shields small, narrow, 

 rounded without ; acute-angular within ; side-shields large, angular ; 

 ventral arm-plates widely separated, elongated, rounded on the outer 

 edge ; the inner end with an angular median point. Diameter of disk, 

 3 5inm . length of arms, about 22°''". Probably young, but very unlike 

 the young of any of our other species. 



Mostly off Nova Scotia, in 220 to 858 fathoms, on Gorgonians. 



