OPHIUROIDEA 



195 



5. Ophiacaniha densa Farran. (Fig. 108.) 



Disk closely covered with small rod-like glassy spinules, which 

 are only slightly bifid or trifid at the tip ; scales of disk, as well 

 as radial shields, not visible. Dorsal arm plates small, triangular, 

 with convex outer edge, widely separated even at base of arm. 

 Ventral plates with almost semicircular outer edge, widely 

 separated. 1 small, smooth tentacle scale. 4 slender, smooth 



Fig. 108. — Ophiacantha densa; part of dorsal (upper figure) and oral side 

 (lower figure). {Alter FarTa.n, Deep- Water A-st. . . . Ireland.) xca. 6. 



arm spines, the uppermost at base of arm as long as two arm 

 joints. 3 subequal mouth papillae. Mouth shields lozenge- 

 shaped, with a convex outer edge. Colour in Life not recorded. 

 Diameter of disk up to 4-5 mm., by an arm length of ca. 20 mm. 

 This species has till now been found only in the British seas, 

 off S.W. Ireland (50° 39' N., 11° 14' W., 50° 42' N., 11° 18' W., 

 53° 7' N., 14° 50' W., in depths of ca. 740-1310 m., " Helga "). 



