494 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



are small notches between the individual ossicles. The postradial series are separated 

 slightly or not at all, and thus are often in close contact. 



There are not more than 30 arms, usually about 30, which are from 75 to 105 

 mm. long. The arms are long and slender with a smooth dorsal surface and short 

 brachials. The first brachial is almost rhombic and is closely united interiorly with 

 its neighbor. The second brachial is a little longer exteriorly than ulteriorly. The 

 first syzygial pair (composed of brachials 3+4) is markedly broader than long. The 

 next four brachials are short and discoidal, and those succeeding are almost triangular, 

 later passing over into bluntly wedge-shaped. The distal brachials are more Rec- 

 tangular, and the terminal almost square. Syzygies occur between brachials 3+4, 

 again from between brachials 14+15 to between brachials 23+24, and distally at 

 intervals of 6 to 13 (usually 9 or 10) muscular articulations. 



The lower pinnules are equally stout on all the arms, and are of approximately 

 equal length on both sides of the arms. They are moderately stiff, although they 

 are never styliform. Even the pinnules of the first pair may be rather stiff. The 

 pinnules of the first pair are slender, becoming very slender terminally, and are com- 

 posed of 16-20 elbngated segments. They are markedly shorter than the pinnules of 

 the second pair, which are much thicker and stiffer; these reach 10-12 mm. in length 

 and are composed of 12-20 segments, which gradually become slenderer and which 

 are mostly longer than broad. The pinnules of the next pair (P 3 and PC) are usually 

 shorter and taper more strongly, though they are always longer and thicker than the 

 pinnules of the first pair. The length of the pinnules of the two following pairs 

 decreases. The pinnules of the sixth pair measure about 5 mm. From the seventh 

 pair onward the length of the pinnules increases, finally reaching about 8 mm. 



The disk is 14-16 mm. in diameter and is strongly incised. Sacculi are thickly 

 set on the pinnules. In color the central portion of the dorsal surface is light yellow- 

 ish brown or gray-brown; on the arms dark and light shadings of brown alternate. 

 The disk is dark gray-brown variegated with gray, or uniformly gray-brown. Or 

 the central part of the dorsal surface is white or light brownish white, the distal half 

 of the cirri dark brown with the exception of the terminal claw, which is white, and 

 the arms broadly banded with white or light gray-brown and darker; the disk is 

 gray-brown variegated with white or light brownish white. 



Hartlaub said that he had examined the type specimen of brevicuneata at Leyden 

 and had convinced himself that it shows the closest agreement, especially in its general 

 habitus, with the specimens that he had described as amboinensis. If in spite of 

 this he had permitted himself to refrain from identifying the specimens from Amboina 

 with brevicuneata in his preliminary paper, it was because, apart from a lesser number 

 of arms, a feature that he originally believed to be characteristic of that form the 

 lateral flattening of the postradial series was lacking. He was confirmed in his belief 

 that the lateral flattening of the postradial series is a fundamental character of brevi- 

 cuneata by a study of a number of specimens from Mortlock Island that, without 

 exception, show this feature very highly developed. Besides this, Dr. P. H. Car- 

 penter wrote him briefly that he did not consider as brevicuneata one of Brock's speci- 

 mens from Amboina that was sent him for an opinion. In suppressing Antedon 

 amboinensis in his later memoir he was simply following his original opinion. The 

 motive for this was given by a second letter from Carpenter, which induced him to 



