386 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



The cirri are usually about XV, rarely so many as XVIII (as in a specimen from 

 Charleston), with the segments commonly 10 in number. The cirri are short, from 

 6 to 7 mm. in length, and moderately slender. The first 2 segments are short, those 

 following being somewhat elongated and approximately of the same length, though 

 the third and fourth are sometimes longer than the others. The segments are cylin- 

 drical, slightly constricted centrally, with the distal edge scarcely produced. There 

 are no dorsal spines and the opposing spine is usually feebly developed. The ter- 

 minal segment (in specimens from Cape Frio) is sometimes much compressed. 



The radials are visible in young specimens (Cape Frio). In young individuals 

 (as all the specimens from Cape Frio) the IBri are short and laterally free, but in 

 older examples they are in lateral contact, and the apposed sides are somewhat thick- 

 ened. The IBr2 (axillaries) are short, almost or quite triangular, with the distal sides 

 slightly concave. The dorsal surface is either smooth and evenly rounded (French 

 Reef and Blake station 249), or these ossicles have somewhat everted distal edges 

 (Dominica). 



There are 10 arms. The first brachials are short and discoidal, and are rarely 

 wholly in contact interiorly; in the yoimg (Cape Frio) they are entirely free. The 

 second brachials are also short, somewhat longer exteriorly than interiorly, and have 

 a slightly produced angle on the distal border, which occurs on all the brachials fol- 

 lowing. They are free interiorly, though sometimes they are very close together 

 (as in a single specimen from Martinique). The first syzygial pair (composed of 

 brachials 3 + 4) is usually short and, like the following brachials, discoidal, rarely so 

 long as broad (Cape Frio). The fifth brachial is sometimes (as in specimens from 

 French Reef and Cape Frio) provided with a process directed proximally on its lower 

 border. A similar process sometimes also occurs (Martinique) on the short wedge- 

 shaped sLxth brachial. From the seventh onward the brachials become triangular and 

 are at first as a rule very short (somewhat longer in the specimens from Cape Frio). 

 The distal edge of the brachials is always concave; the proximal border may also be 

 concave (Cape Frio), but it is more commonly toothed and rarely (Martinique) 

 straight. 



The distal edge of all of these triangular brachials is more or less strongly everted 

 and dentate, sometimes also including the syzygial lines. The produced distal borders 

 overlap the following brachials only very slightly if at all. At about the twenty-second 

 the length of the triangular brachials increases. In the younger individuals, in which 

 the proximal portion of the arm is much smoother than in the older, the triangular 

 brachials earlier pass over into a bluntly wedge-shaped form with a correlated increase 

 in length. In older examples (those from Martinique and certain individuals from 

 French Reef) the brachials first become wedge-shaped, as a rule at about the thirtieth, 

 while in certain others {Blake stations 155 and 249) they remain sharply triangular 

 until the sixtieth. The outermost brachials are elongated and somewhat wedge- 

 shaped. In the distal half of the arms the dorsal surface becomes markedly smoother. 

 Except for those at the base of the arms, the syzygial pairs are always longer and less 

 wedge-shaped than the adjacent brachials. The greatest width of the arms is from 

 1.5 to 2 mm., and is usually at the base, more rarely at about the sixteenth brachial. 

 The width, especially on the short posterior arms, decreases very rapidly, so that 



