﻿102 OPIIIOPIiOLIS CARYL 



.7 : .6. Upper arm-plates irregular oval, with outer side most curved ; 

 length to breadth (third plate), .6 : 1. Supplementary pieces irregular, 

 but usually oblong and angular, the largest ones near lateral corners of 

 each plate ; near base of arm, eight or nine to each plate ; near the end 

 of the arm there are still eight or nine supplementary pieces, but the 

 upper arm-j)lates are nearly round. Disk, above, closely and perfectly 

 covered with small rounded grains ; about 100 to a square 7nm. ; below, 

 interbrachial spaces thickly beset with very short, stout, sharp spines, 

 about .I""- long. Arm-spines five, sometimes six ; short, stout, blunt, 

 more or less flattened ; three upper ones largest ; second spine stoutest 

 and broadest of all ; two lowest smaller and more conical ; lengths to 

 that of under arm-plate (eighth joint), .5, .5, .5, .4, .3 : .7 ; near tip of 

 arm, spines more rounded and tapering. Tentacle-scale one, thin, flat, 

 narrowest at the base, cut off square at the end, about as long as lowest 

 arm-spine. Color, in alcohol : above, nearly uniform lake-pink, a little 

 deej)er near edges of disk ; along arms a faint, broken line of lighter ; 

 below, interbrachial spaces, near edge of disk, same as upper surfiice, 

 but fading to nearly white towards the mouth ; under arm-plates and 

 mouth-parts white, the former edged with reddish along their lateral 

 sides ; side arm-plates and arm-spines same as upper surface, but 

 lighter. 



Variations. — A young one, with a disk of 2.7""°", had arms 7.6""'' in 

 length ; the color was mottled pink and white j the disk was pretty 

 closely covered with grains, or very short spines, each bearing a crown 

 of three little thorns ; the arm-spines were rounded and conical, but 

 not at all flattened. Another specimen had a disk of only 2.2'""'', and 

 arms of 8.1""°- ; this had all the supplementary pieces of the upper arm- 

 plates covered with minute thorns. The smallest specimen had a disk 

 of l.D"™', and arms of 5.4°"- ; the disk granulation, arm-spines, mouth- 

 papilliB, and supplementary pieces of the arm-plates, were all thorny ; 

 arm-spines five ; mouth-papillge two ; lower arm-plates longer than 

 broad, narrowest within, with a re-entering curve on the outer side, and 

 a notch on the inner ; upper arra-^jlates longer than broad, rounded. 



This small species is distmguished from 0. Kennerlyi and 0. hellis by 

 having the disk entirely covered with fine grains, without naked plates. 



It is not impossible that this may be but a variety of 0. Kennerlyi ; 

 but as I have seen the young of both, with the distinctive specific marks, 

 I prefer to keep the names as they now stand. 



