236 



ECHINODERMS OF THE BRITISH ISLES 



Dorsal arm plates merely in contact on the proximal joints, with 

 an acute proximal angle and a strongly convex, in the middle 

 slightly elevated outer edge. Smaller scales of disk not 

 forming regular circles around the primaries O. Grubei Heller 

 13. Mouth shields twice as long as broad . 7. O. affinis Ltk. 



Mouth shields scarcely longer than broad 8. O. signata (Verr.) 



1. Ophiura texturata Lamarck. (Fig. 128, 3-4.) 



(Syn. Ophioglypha ciliaris (Linn.) ; 0. ciliata (Retzius) ; O. lacer- 

 tosa (Pennant) ; Ophiura ophiura (Linn.) H. L. Clark.) 



Scales of disk rather coarse ; primary plates fairly distinct, 

 especially the central plate. Radial shields about haK the length 



Fig. 128. — 1-2. Ophiura Sarsi. 3-4. O. texturata. 5-6. O. albida. The 

 upper figures represent part of the oral side, the lower figures of the 

 dorsal side. x 4. (From Danmark's Fauna.) 



of the disk radius, separated or contiguous at their broadest part, 

 just inside the innermost dorsal plate. Arm combs consisting of 

 very fine, rather long papillae, ca. 30 in the outer comb. The inner- 

 most of the dorsal plates in the notch above the arm (there are 

 generally 4 of them) usually rectangular or triangular. The free 

 dorsal plates in the proximal part of arms four to five times as 

 broad as long, with straight or slightl}^ concave outer edge, 

 contiguous throughout their whole breadth. Dorsal side of arm 

 somewhat roof -shaped. Ventral plates twice as broad as long, 

 with convex outer edge ; they are not contiguous, but separated 

 by a pair of sharply defined pore-shaj)ed grooves in the mid-line 



