118 AJUPHIURA HOLBOLLL 



Amphiura Holbblli Lutken. 



Amphiura HolbolU Lutken. Vidonsk. Meddelelser. Nov., 1854. 

 Amphiura HolbolU Lutkex. Addlt. ad Hist. Oph., p. 55. 



Special Marks. — Middle mouth-papilla placed higher than the others; 

 one tentacle-scale ; under arm-plates pentagonal. 



Description of a Specimen. — Diameter of disk, 7.5°^- ; from outer 

 side of mouth-shield to outer corner of opposite mouth-slit, 3.3°""- ; 

 width of arm without spines, 1.4""- ; length of arm, SO""""" ; distance 

 from outer side of mouth-shield to inner points of mouth-j)apilla}, to 

 that between outer corners of mouth-slits, 1.7 : 1.5. Mouth-papilla?, six 

 to each angle of mouth ; two innermost stoutest, pointing to centre of 

 mouth, oblong ; running upwards to the teeth ; innermost papilla 

 attached to side mouth-shield, small, flat, with a curved, cutting edge ; 

 middle pajiilla? placed near the innermost one, and a little higher up ; 

 long, sharp, like a canine tooth. Teeth four ; two uppermost large, flat, 

 longer than broad, squarish, rather thick ; next one smaller, stouter, 

 sharper ; lowest one very short and thick, presenting a broad, grinding 

 surface. Mouth-shields rounded, truncated, and narrower without ; 

 length to breadth, .7 : .7 ; madreporic shield nearly twice as large as 

 the rest, and bearing pores on its edge. Side mouth-shields large, broad 

 triangular, with all their sides re-enteringly curved ; meeting within, 

 and also meeting their neighbors between the first and second under 

 arm-plates. Under arm-plates about as long as broad, regularly pen- 

 tagonal, the fifth angle being very obtuse, and directed inwards ; length 

 to breadth (thirteenth plate), .6 : .5 ; first plate nearly hidden by side 

 mouth-shields. Side arm-plates narrow, encroaching so as almost to 

 meet both above and below. Upper arm-plates broader than long, 

 pointed oval, more curved within than without, the inner curve making 

 a faint angle ; length to breadth (sixth plate), .6 : 1.2. Disk-scales 

 about 20 to a square mm. ; some of the primary plates, especially those 

 in the centre, still to be distinguished ; scales of interbrachial spaces 

 below much finer. Radial shields small, narrow oval, with inner end 

 pointed ; length to breadth, 1.2 : .5 ; widely separated from each other 

 by a broad wedge of scales. Arm-spines three, near the disk four, 

 nearly equal, stout, nearly cylindrical, blunt, hardly tapering ; upper 

 one rather the stoutest and most tapering ; lengths to that of under 

 arm-plate (tenth joint), .6 : .6. Tentacle-scale one, small, rounded, 

 standing within the tentacle pore. Color, in alcohol : disk, brownish 

 gray ; arms the same, but browner. 



