83 



Lütken has pointed out that there may sometimes be found 

 a third, small tentacle scale besides the two normal ones. In 

 these specimens two and three tentacle scales are found equally 

 often, and not only on the inner armjoints, but farther out, 

 until about the 16**^ joint. Sometimes there are even 4 tentacle 

 scales on some of the inner joints. On the other hand, I have 

 seen none with only one tentacle scale, as in some specimens 

 from Greenland, mentioned by Lütken. In some specimens 

 the armcomb is very little developed or even totally wanting; 

 these specimens, however, are in no other respect different 

 from the typical form. 



It is a noticeable fact that all the numerous specimens are 

 of about the same size (15 — 20 mm. diameter of the disc); as 

 numerous specimens of the small 0. robusta are taken in the 

 same haul, the small specimens of 0. Sarsii cannot have been 

 overlooked; really none have been living here together vv^ith the 

 large specimens. Otherwise it is a common thing to find all 

 different sizes represented in places, where some species occurs 

 in great numbers; by measuring the specimens of different sizes 

 from such a locality it may be possible to show the age of the 

 specimens — as I have done elsewhere for 0. texturata. (Smaa 

 Biologiske Meddelelser. Vidensk. Medd. Naturh. Foren. Køben- 

 havn. 1897. p. 321). How this may be in 0. Sarsii, I dare 

 not say; the occurrence of only one size on the locality named 

 might mean that they are only one year old. 



18. OpMoglypba robusta (Ayres). 



Ophiura squamosa Lütken. 



Lütken : Additamenta. p. 46. — Duncan & Sladen: Op. cit. p. 62. — 

 Bell: Op. cit. p. 109. — Grieg: Op. cit. p. 262. 



Jan Mayen, 15 fathoms, 1 specimen. — Jan Mayen, 50—60 

 fath., numerous sp. — Henry Land, 20 fath., 2 sp. — Sabine 

 Island, anchoring place; 4 sp. — Кар Tobin, 57 fath., 2 sp. — 

 Rathbom Island, 94 fath., 2 sp. — Hurry Inlet, 10 fath., 1 sp, 



6* 



