Boone, Echinodermata, Cruises of "Eagle" and "Ara," 1921-28 107 



The young when quite small differ a great deal from the adult. 

 They are frequently found clinging to the arms or disk of the parent. 



Color: Agassiz's colored drawings made from living animals and 

 first published by Dr. Lyman show this species to possess much varia- 

 tion. The ground color of the disk is almost always variegated, being 

 variously dull indigo-blue, different shades of greenish, yellowish 

 brown, yellow, gray or brownish flesh color, with the radial shields 

 usually different from the disk, either bright or dull green, dark 

 brown, lake-red, bluish, dull brown or gray; the arms also usually 

 differ from the disk and are usually banded ; one specimen had them 

 sap-green, another lake-red and yet another brownish flesh color 

 banded with black. The tentacles are red. 



Technical description : Disk orbicular, diameter 7 mm., length of 

 arm 64 mm. or slightly more than nine times as long as the disk 

 diameter. Abactinal surface of disk and lateral margins covered with 

 small, flat, overlapping scales of uneven sizes. (Covering of central 

 portion of disk torn off in the present specimen.) Five to six larger 

 scales form a line between the radial shields. These shields are rather 

 slender, pear-seed shape with the apex directed inward, the outer 

 margin rounded ; the length 2.1 mm., the greatest width 0.8 mm. The 

 outer margin of the radial shield is separated from the first arm-plate 

 by several small scales. The interbrachial region of the actinal surface 

 is covered by tough skin and along the margin of the genital slit 

 there are small, tapered papillae, also a few on the interbrachial 

 region. The mouth-shields are small, suboval, wider than long, the 

 outer margin more dilated than the inner. The side mouth-shields 

 are long, narrow, meeting on the inner side. There are nine blunt, 

 squarish teeth which are thickened on the median cutting edge. The 

 mouth papillae are small, rounded, flattened, placed two in each angle 

 at the base of the jaw-frames. The under arm-plates are slightly 

 wider than long, with the outer margin slightly convex, the outer 

 corners rounded, the inner margin is less convex than the outer but 

 also with its corners rounded; the lateral margins are concave; the 

 plate has the appearance almost of a shield with the angles rounded. 

 There is one rather large, oval tentacle scale. The side arm-plates 

 are wider than long, encroaching but little upon the surface of the 

 upper arm, and supporting seven arm-spines. The upper arm-plates 

 are nearly twice as wide as long, with both the inner and outer 

 margins relatively straight with the lateral angles rounded. The 



