﻿OPIIIOCOMA PUMILA. 



71 



One tentacle-scale, 



Two tentacle-scales, 



GROUPING OF SPECIES HEREIN DESCRIBED. 



0. Valencice. 

 0. pumila. 

 0. Alexandri. 

 0. Riisei. 

 Near base of arm, sometimes two tentacle-scales, 0. <ethiops. 

 Ai-m-sjiines about equal, 0. nigra. 



( 0. echinata. 

 Upper arm-spines longest, < 0. erinaceus. 



V 0. scolopendrina. 

 Lowest arm-spine longest, 0. insularia. 



Six slender arm-spines ; disk and arms lined and ^ ^ 



spotted, j 



Disk granulation very fine and close ; spines ) 



regular, j 



. pica. 

 0. hrevipes. 



OpMocoma Valencise Mijll. & Trosch. 



Opldocoma Valenckc MOll. & TitosCH. Syst. Asterid., p. 102. 

 LIST OF SPECIMENS. 



OpMocoma pumila LijTKEN. 



Ophiocoma pumila LxJTKEN. Vidensk. Meddelelser. Jan., 1856. 

 OpMocoma placentigera Lutken. [Labelled specimens.] 

 OpMocoma pumila LtJTKEN. Addit. ad Hist. Oph., p. 146. 



Special Marks. ■ 

 longest. 



Commonly five arm-spines ; first or second spine 



Descrijitioii of a Sjoechnen. — Diameter of disk, IS"""' ; fi'om outer 

 edge of mouth-shield to outer corner of opposite mouth-slit, S""' ; 

 greatest width of arm without spines, 2.2°™- ; length of arm about YS"""" ; 

 distance from outer edge of mouth-shields to inner point of tooth- 

 papiUaj, to that between outer corners of mouth-slits, 2.5 : 2.5. Mouth- 

 papillge short, stout, longer than broad, much rounded, often nearly egg- 

 shaped, somewhat irregularly disposed ; innermost one more pointed 

 and tooth-like ; about fourteen to each angle of mouth. Tooth-papilla3 



