MUSEUM OF COMPARATIVE ZOOLOGY. 275 



Ophiochondrus crassispinus sp. nov. 



Plate VII. Figs. 111-113. 



Special Marks. — Seven or eight thick, short, blunt, slightly rough arm-spines. 

 Eadial shields long and prominent. Month-papillae sharp and separated. 



Description of an Individual. ■ — Diameter of disk 6 mm. Length of arm 

 20 mm. "Width of arm close to disk 2 mm. Three short, stout, sharp mouth- 

 papillse on each side of an angle, and one similar but larger at the apex; this 

 last may be considered as the lowest tooth. Mouth-shields somewhat swollen, 

 about as broad as long, with an angle inward. Side mouth-shields large, thick 

 and wide; broader without than within where thej^ meet. First under arm- 

 plate small, longer than broad, with an angle inward. Those beyond are sep- 

 arated one from another, and are four-sided and much wider than long, with a 

 slight re-entering curve without. Side arm-plates with narroM', prominent 

 spine-ridges; meeting below but separated above by fan-shaped uppej arm- 

 plates which present a truncated angle inward. Disk thick, sparsel}' beset 

 with a fine granulation, except on the radial shields which are prominent and 

 large; they are much, longer than broad, wider without than within, and sepa- 

 rated; their ends are rounded; length to breadth, 2 : .6. Seven or eight short, 

 blunt, slightly rough arm-spines, which stand at a considerable angle to the 

 arm; they are nearly equal and not so long as a joint; those in the middle 

 often are swollen at their base. No tentacle-scales. Color in alcohol, pale 

 straw. 



Station 316, 32° 7' N., 78° 37' 30" W., 229 fathoms, 1 specimen. 



This species is well distinguished from 0. stelliger by its great naked radial 

 shields and numerous arm-spines; and from 0. convolutus by different mouth- 

 papillae and no tentacle-scale. 



Ophiochondrus squamosus. 



Plate VII. Figs. 108-110. 



Special Marks. — Disk covered above by thick, lumpy, separated plates, and 

 below by lumpy scales. Seven or eight short conical arm-spines. Lower arm- 

 plates obscured by thick skin. 



Description of an Individual. — Diameter of disk 6.5 mm. Length of aim 

 40 mm. Width of arm near disk without spines 1.3 mm. Three small, some- 

 what flattened, separated papillas on each side of a mouth-angle, whose apex is 

 occupied by the lowest tooth, which is large and of a wide spear-head shape. 

 Mouth-shields small, of a transverse oval form; lengtU to breadth, .5 : .6. 

 Side mouth-shields scarcely visible under the thick skin ; they are narrow and 

 meet within. Basal under arm-plates obscured by thick skin ; farther out on 

 arm, they appear as thick, widely separated transverse oval plates, and near 

 the end they are squarish and nearly or quite touch each other. Side arm- 



