254 



mouth-shields and under arm-plates irregularly edged and spotted 

 with dark blue. 



Variations. Another specimen had but few of the longest 

 spines on the disc, most of them being of the second or of the 

 smallest size ; the radial shields had no distinct spots, and the 

 under arm-plates were mostly bright blue. The side mouth- 

 shields sometimes do not meet within. 



This species differs from 0. spiculaia, 0. violacea, and 0. an- 

 gulata in the armature of the disc, which is coarser and of a dif- 

 ferent character ; the two latter species, also, are smaller. 



San Diego, Cal. Mr. Cassidy. 



Smithsonian Institution, No. 1049. 



Ophiothrix magnijica, (Lyman,) sp. nov. 



Description of a Specimen. Diameter of disc, 12.5 millim. 

 Length of arm, 70 millim. Tooth-papillae about 36, in two verti- 

 cal, diverging rows of about 10 papilliB each, filled in between with 

 smaller papilh^. Teeth 6, with a squarish cutting edge ; rather 

 thick ; uppermost one thinner, and tapering almost to a sharp 

 point. Mouth-shields small, almost circular ; length to breadth, 

 1 : 1.2. Side mouth-shields meeting within. Under arm-plates 

 irreo-ular oval ; closely joined to each other, and covered with 

 thick skin, so that their outlines are indistinct ; length to breadth, 

 .7 : 1.3. Upper arm-plates small, with a strong median ridge ; 

 diamond-shaped, with the outer angle strongly rounded ; length 

 to breadth, (13th plate,) .7 : 1.2. Brachial and interbrachial 

 rays closely beset with round, stout, tapering spines, of very 

 even length ; they are covered with minute thorns, and terminate 

 in a crown of the same ; these spines have usually a length of 1.3 

 millim. Radial shields bearing only a few small spines ; length 

 to breadth, 3.5 : 1.7. Arm-spines stout, rather blunt, rounded, 

 slightly and regularly tapering, bearing many small thorns, and 

 deeply corrugated lengthwise ; second and third spines usually 

 longest and stoutest; 11th joint, 8 spines; lengths to that of un- 

 der 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, disc dull indigo blue ; arms the same, but banded with 

 lighter, usually two or three joints to each band ; arm-spines 

 faint blue ; below, under arm-plates variegated with cross-lines 



