232 ECHINODERMS OF THE BRITISH ISLES 



Arm combs represented by a more or less distinct double series of 

 granules ; mouth shields usually undivided or with a small 

 supplementary plate at inner corner. {''Monaco'', xxxiv. 

 ri. XXV. 12-13, PI. XXVII. 5-6) . . H. tessdata (Verr.) 



Arm combs small, but consisting of distinct papillae ; mouth shields 

 usually divided through a longitudinal line. {''Challenger'' 

 Op;?., PL III. 10-12) .... H. inornata{hym.) 



[Ophiozonella Matsumoto.] 



The two species of this genus known from the N.E. Atlantic 

 are : 0. molesta (Koehler) (Syn. Ophiozona molesta Koehler), found 

 off the Canaries, 2115 m. (" Talisman "), elsewhere known from 

 the Malay Archipelago, 1270 m. (" Siboga ") ; 0. sincera 

 (Koehler) (Syn. Ophiozona sincera Koehler), found in the Bay of 

 Biscay, 1226- 1600 m. (" Talisman "). These two species, w^hich 

 have both of them a very conspicuous rosette of primary plates 

 and two small arm spines, are thus distinguished : 



A single large tentacle scale (" Talisman" Oph., PL XVIII. 4-5) 



0. sincera (Koehler) 



Two tentacle scales, one outside the other ("Siboga" Oph., i. 



PL VI. 3-5) O. molesta (Koehler) 



I. Ophiura Lamarck. 



(Syn. Ophioglypha Lyman.) 



Disk flat, covered with numerous small scales, among which 

 the primary plates are usually inconspicuous. Edge of disk not 

 sharp ; usually there is a conspicuous notch above the base of 

 arms, in which some rudimentary dorsal plates are situated ; 

 it has thus more or less the appearance of the arms issuing 

 from the dorsal side of disk. On each side of the notch usually 

 a more or less distinct comb of papillae, continuing along the side 

 of arm down to the ventral side and passing gradually into the 

 genital papillae along the bursal slits ; more rarely the outer 

 combs unite across the base of arms. Another pair of smaller 

 combs of papillae, the secondary arm combs, is found on the 

 dorsal side of the base of arm, usually rather inconspicuous and 

 covered by the outer comb. Ventral plates usually triangular, 

 much broader than long, with a proximal angle ; mostly they 

 are widely separated, but a few of the proximal ones may be 

 contiguous. Second tentacle pore outside the mouth edge, but 

 usually opening into the mouth slit. The pores continuing to the 



