238 ECHINODERMS OF THE BRITISH ISLES 



In British seas this species occurs more or less commonly 

 all round the coasts, from about lower tide limit to ca. 200 metres 

 depth. At Fano on the coast of Jutland, and on the French 

 coasts, it has been observed above the lower tide limit ; before 

 the water disappears it buries itself in the sand, but it soon rises 

 and tries to reach the water, a characteristic star-shaped groove 

 in the sand showing the place where it had buried itself. It 

 is distributed from Lofoten on the Norwegian coast to the 

 Danish seas (not the Baltic), and farther to the Mediterranean 

 and Madeira. It is not found at Greenland or the N. American 

 coasts. In the Mediterranean it may be found in depths to 

 300 m. ; elsewhere it scarcely goes deeper than 200 m. 



2. Ophiura Sarsi Llitken. (Fig. 128, 1-2.) 

 (Syn. Ophioglypha Sarsi Ltk.) 



Scales of disk rather coarse, primary plates generally dis- 

 tinct. Radial shields as in texturata. Arm combs consisting 

 of short, rather broad papillae, ca. 9-12 in the outer comb. The 

 innermost of the dorsal plates in the notch usually triangular or 

 rectangular. Dorsal and ventral plates of arm mainly as in 

 texturata, but there are no grooves between the proximal ventral 

 plates. The proximal {i.e. third) pore pair with 3-4 tentacle 

 scales at the inner edge, the following ones with 2 tentacle scales, 

 farther out only 1. The innermost pairs also have 3-4 scales at 

 the outer edge, the following ones 2, those just outside the disk 

 only 1 minute scale, which disappears at about the tenth pore 

 pair. Arm spines 3, placed at equal distances from one another, 

 often somewhat outstanding. In proximal part of arm the two 

 uppermost spines are up to twice the length of a side plate, while 

 the lower spine is somewhat shorter ; sometimes also the upper 

 spine is shorter than the middle one. Arms somewhat roof- 

 shaped, arched. Mouth shields conspicuously shorter than the 

 distance from their outer edge to edge of disk. Four to six pointed 

 mouth papillae. Colour in life reddish or darker, often somewhat 

 mottled. In young specimens the distal part of the radial 

 shields may be white, as in 0. albida and robusta ; in fact, the 

 resemblance between 0. robusta and Sarsi of a corresponding 

 size may be so great that a closer examination is necessary for 

 distinguishing them. Grows to about the same size as 0. tex- 

 turata ; arms ca. four times the diameter of disk. 



Development unknown ; but there are reasons for suggesting 

 that Ophiopluteus compressus (Fig. 3, 3 and 88, 6) may be the 



