﻿80 



OPHIOCOMA ^THIOPS. 



Variations. — In other specimens the disk was to the arms as 29 : 145, 

 32 : 162, 10.5 : 56. Tentacle-scales vary much in number on specimens 

 of same size, and even on same individual ; occasionally there are regu- 

 larly two scales to each pore as far out as the thirty-third joint, but this 

 is unusual. Tooth-papillse commonly arranged in five regular horizontal 

 rows, of three each. Granulation of disk does not always cover whole 

 of interbrachial spaces below, but a broad band may be left running 

 along the genital slits, and outside the mouth-shield. Color varies to a 

 certain extent. It may be even dirty white, blotched with dark broAvn, 

 on the upper side of the disk, with lower side of arms very light brown, 

 the lower arm-plates Jseing more or less mottled ; extremities of arms 

 may be banded with darker and lighter. A young one having a disk 

 of 10.5°"°' was similar to the larger specimens, but had the arms banded 

 for their whole length, the arm-plates speckled with lighter, the mouth- 

 papilljB regular and bead-like, and the tooth-j)apillte in horizontal rows 

 of only two each. 



This species is distinguished from 0. echlnata and O. Biisei by wider 

 and flatter arms, and by differently shaped arm-spines and mouth- 

 shields. 



LIST OF SPECIMENS. 



303 

 304 

 305 



1007 

 1008 

 1011 

 1185 



Museum of Comparative Zoology. 



12+ 

 12+ 



7 



Acapulco, Mexico. 



Panama. 



Panama. 



Cape St. Lucas, Cal. 



Smithsonian Institution. 



Panama. 



Panama. 



Panama. 



West Coast Nicarafrua. 



Cape St. Lucas, Cal. 



Cape St. Lucas, Cal. 



Alex. Agassiz. 

 Alex. Agassiz. 

 Alex. Agassiz. 



Dr. Sternbergh. 

 Rev. T. PoweU. 

 Dr. Suckley. 

 Capt. Dow. 

 J. Xantus. 

 J. Xantus. 



Dried. 

 Alcoholic 



