OPIIKXJLYPIIA SARSII. 41 



Ophioglypha Sarsii Lyaiax. (Fii^s. 2, 3.) 



Oph'nird artifcni AcASS. Proceed. Am. Acad., IH.'jl, p. 200. [No description.] 



0/)/ii(>l(j)is ciliala Stimps. Inverteb. of Grand Maiuui. Sniillison. Contrili., ^'I. p. 13. 1854. 



Oph'ntra coriacea Lutken. Vidensk. Mcddelelser. Nov., 18.">l. 



Ophiura arclica ? Lutkk.V. Vidensk. Meddelelser. Nov., 1854. 



Opiiiiira Sarsii Lutkex. Vidensk. Meddelelser. Nov., 1854, 



Ophiura Sarsii I^utkkx. Addit. ad Mist. Opii., p. 42. 



Sj)ecial Marks. — Anns, in the adult, three or four times as lono; as 

 (liaiueter of disk ; longest arm-spine about as long as an arm-joint ; 

 primnry plates much larger than the intermediate disk-scales. 



Descfnjjtion of a Specimen. — Diameter of disk, 17.8"'"'-; from outer 

 edge of mouth-shield to outer corner of opposite mouth-.'^lit, 8"""' ; width 

 of arm, without spines, 3.5"""'; length of arm, 60""" ; distance from outer 

 edge of mouth-shield to inner points of mouth-papilla}, to that between 

 outer corners of mouth-slits, 4.6 : 3.4. Mouth-papilla) usually thirteen to 

 each angle of mouth, namely, six on each side, and one at apex of angle ; 

 sometimes seven on each side, or again only five ; the papilla at the 

 apex points directly to centre of mouth, and is about twice as large as 

 any of the others ; it has a diamond or spear-head shape ; rest of papilla? 

 small, flat, short, and rather sharp ; outer ones smallest ; outermost one 

 usually l)roader and lower than others, being shaped like a cutting edge. 

 Teeth shaped like innermost mouth-papilla, usually four, but sometimes 

 live in number. Mouth-shields longer than broad, bounded by a curve 

 without, an angle Avithin, and laterally by straight lines ; length to 

 breadth, 2.4 : 2 ; length of sides bounding inner angle, 1.4"™- ; madre- 

 poric shield rather smaller and more rounded, Avith a slight rising in the 

 middle. Side mouth-shields curved, and very long and narrow ; starting 

 from inner end of mouth-slits, they follow the sides of the mouth-shield, 

 and meet at its inner point ; length to breadth, 2.4 : .6. Under arm- 

 plates covered in good part, even at base of arm, by side arm-plates ; 

 all of them, therefore, are much broader than long, and are bounded 

 only ])y three sides, viz., one outer side nearly straight, and two inner 

 laterals, wdiich are a little re-enteringly curved, and which slope from 

 outer corners of plate towards its middle line, on which they meet in a 

 point ; the shape is that of a very short triangle, the point Ijeing directed 

 inward. First plate unusually large, nearly oval, length to breadth, 1:2; 

 second plate of usual shape, but a little longer than those immediately 

 following, length to breadth, 1:2; length of inner lateral, 1.4"™' ; twen- 

 tieth plate, .6 : 1.2 ; plates about two thirds out on arm, .4 : .8 ; close to 

 tip of arm, plates so covered as to be scarcely perceptible ; they are not 

 more than one half or one third the width of the arm, and are bounded 

 Ijy six sides, two outer lateral > and two inner laterals, sloping towards 



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