244 ECHINODERMS OF THE BRITISH ISLES 



7. Oi^liiura affinis Liitken. (Fig. 84, upper part ; Fig. 132.) 



(Syn. Ophioglypha affinis (Ltk.) ; Ophiura Normani Hodge.) 



Disk flat and regularly covered with fine scales so arranged 

 as to form a regular circle around the very conspicuous primary 

 plates ; these latter are round, the small scales usually quad- 

 ranguhir. Radial shields small, only ca. J the disk radius ; they 

 are wholly separate. Arm combs consisting of ca. 7-9 short, flat 

 papillae; the inner combs, w^hich consist of ca. 10 somewhat smaller 

 papillae, are contiguous in the mid-line, thus forming a continuous 

 comb above the arm base. A few papillae are often found on the 

 edge of disk in the mid-line of the notch, just above the secondary 

 comb. The notch is small, containing only two small dorsal 

 plates, the innermost one quite small, wart-shaped. Dorsal 

 plates of arms very broad, roof -shaped ; ventral plates widely 



separated, with a small, very obtuse 

 proximal angle and very convex 

 outer edge. Three small equidis- 

 tant arm spines, the uppermost the 

 longest, as long as an arm -joint. 

 Only one rather broad tentacle scale ; 

 the two proximal pore pairs also with 

 a small scale at the outer edge. The 

 second tentacle pore, which has like- 

 FiG. 132. — Ophiura affinis; wlse only one tentacle scale on each 

 part of oral side x 8 g-^^ ^^^^ ^^^ ^ ^^^^ ^^le mouth 



{From. Danmarks Fauna.) ' n i 



silt, contrary to all the species of 



Ophiura described above. Mouth shields large, twice as long as 

 broad, as long as or longer than the distance from their outer 

 edge to edge of disk. Mostly only 3 mouth papillae on each side 

 of jaw, the outer one very broad, scale-Uke. Colour in life 

 reddish-brown or grey. It is a small and delicate form, scarcely 

 exceeding 7-8 mm. diameter of disk ; arms ca. three times the 

 diameter of disk. The arms very easily break off, if the speci- 

 mens are not preserved immediately on being caught. 



The larva not known with certainty, but very probably a 

 somewhat rudimentary Ophiopluteus form (Fig. 133), with 

 apparently only the postero-lateral arms well developed, white, 

 untransparent, belongs to this Ophiuroid. This larva has been 

 found only at the coast of Bohuslen (Sweden) in the beginning 

 of August. 



In British seas this species occurs all round the coasts, from 



