﻿OPIIIURA CINEREA. 27 



Ophiura cinerea Lyjian. 



OpModerma cinereum Mull. & Tnoscn. Syst. Asterid., p. 87. 1842. 

 Ophioderma Antillarum Lutken. Addit. ad Hist. Oph., p. 88. 



Special Marks. — A large species. In adult, upper arm-plates much 

 broken ; mouth-shields broad heartrshaped ; mouth-papillae crowded, 

 numerous, and pretty equal (about twenty) ; arms very round, ta- 

 pering. 



Descrqjtion of a SjMcimen. — Diameter of disk, 20"""- ; from outer 

 edge of mouth-shield to outer corner of opposite mouth-slit, 8""°' ; great- 

 est width of arm without spines, 4.2""°' ; length of arm, 97'""" ; distance 

 from outer edge of mouth-shield to inner points of mouth-papilla}, to 

 that between outer corners of moutl>slits, 4 : 4.4. Mouth-papillae, nine- 

 teen to twenty-one to each angle of mouth (usually twenty), outer one 

 very long and slender, running above next one or two papillae, when 

 mouth is tight shut ; two innermost ones, pointing to centre of mouth, 

 much stouter than others ; of remaining papillae, four inner ones some- 

 what weaker than four outer ones ; all papilla3 crowded, pointed, rounded. 

 Teeth five, flat, somewhat blunt ; the uppermost one longer and sharper. 

 Mouth-shields short heart-shaped, point inward, well rounded, length to 

 breadth, 1.8 : 2.2 ; madrej^oric shield more rounded, and somewhat larger, 

 near its centre a rounded depression ; side mouth-shields entirely covei*ed 

 by granulation. Under arm-plates thick, strong, and firmly set ; bounded 

 by a curved outer side, two long lateral sides a little re-enteringly 

 curved, two very short inner laterals, and an inner side, nearly straight ; 

 towards end of arm, each plate is an octagon, its lateral sides being very 

 long, and its outer and inner laterals very short ; first plate small, irreg- 

 ular oval, with a slight peak inwards, length to breadth, .8 : 1.4 ; second 

 plate, 1.2 : 1.4 ; eleventh plate, 1.2 : 1.4 ; about two thirds out on arm, 

 length to breadth, 1.2 : 1 ; at tip of arm, plates nearly heart-shaped, with 

 point inward. Side arm-plates thick, compact, closely soldered with 

 surrounding parts, their outer edges very conspicuous by reason of 

 shortness of arm-spines ; not meeting above at all, and below only at 

 very tip of arm. Upper arm-plates are all, with exception of first rudi- 

 mentary one, and a few at tip of arm, broken in several pieces, irregular 

 in form, and varying in number from two to five, according to size of 

 plate ; each plate, considered as a whole, makes a belt across arm, of 

 which the inner side is shorter than the outer ; incision in disk embraces 

 first three plates, which are modified in shape accordingly ; fourth plate, 

 broken in four or five pieces, length to breadth, 1.2 : 3.6 ; about two 

 thirds out on arm, some plates are found whole, but most are broken in 

 two or three pieces ; length to breadth, 1 : 2.6 ; close to tip of arm, 



