160 



OPHIOTHRIX MAGNIFICA. 



shields much obscured by surroundmg spines, but bearing only a few 

 small spines themselves; length to breadth, 3.5 : 1.7. Arm-spines stout, 

 rather blunt, rounded, sliglitly and regularly tapering, deeply corru- 

 gated lengthwise, bearing many small, blunt thorns ; upper spines 

 scarcely flattened at all ; second and third spines usually longest and 

 stoutest ; eleventh joint, eight spines ; lengths to that of under arm- 

 plate, 2.4, 2.6, 3.1, 2.1, 2.1, 1.5, .9, .5:. 7. Tentacle-scales distinct, flat, 

 rounded at their outer end. Color, in alcohol : above, disk dull indigo- 

 blue (cobalt and indigo-blue) ; arms the same, but banded with lighter; 

 usually two or three joints to each band ; arm-spines faint blue ; below, 

 interbrachial spaces a little lighter than up23er surface ; under arm-plates 

 variegated with cross lines and specks of white, and of darker and 

 lighter blue, giving the arm a banded appearance. 



Variations. — The general color may incline more to greenish-blue, 

 or, on the other hand, to purplish-blue ; and the marking of the under 

 arm-plates may form more or less distinct bands. The largest specimen 

 had the disk I!""™- in diameter, and some of the spines on the disk as 

 long as 2.1°"^-. Many of the arm-spines were tipped with white. 



This very beautiful Ophlofhrix belongs to the group which has only 

 long spines on the back of the disk ; it differs from 0. Orstedii in 

 greater stoutness and shortness of the disk-spines, and in more cylin- 

 drical arm-spines ; it has more and shorter spines than 0. Suensonii, 

 and is larger than either of these species. 



LIST OF SPECIMENS, 



Catalogue 

 Number. 



Original 

 Number. 



Number 

 of Spec. 



Locality. 



When 

 Collected. 



Whence obtained. 



Nature of 

 Specimen, 



3Iuseu>n of Comparative Zoology. 

 150 I 1043 1 1 I Peru. | | Mr. Raymond. | Alcoholic. 



1043 



Smithsonian Institution. 

 Peru. I I Mr. Raymond. I Alcoholic. 



