408 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Of the 84 specimens from Port Stephens hi the Australian Museum collection 

 one, of moderate size, has 19 arms 55 mm. long and the longest cirri 50 mm. long 

 with 94 segments. The others are of medium size with 15-20 arms. 



The three specimens from Nelsons Bay, Port Stephens, are of medium size. 



The six specimens from Newcastle Bight are medium sized. 



The specimen from Newcastle in 77-88 meters has 19 arms 65 mm. long, two 

 IIBr series are lacking and there is a single externally developed IIIBr series. 



The single specimen from Broken Bay is of medium size. 



Among the 11 specimens from Port Jackson hi the Australian Museum one fine, 

 large example has 19 arms 75 mm. long and the cirri about L, 84-90, from 60 to 65 

 mm. long, the centrodorsal is 4 mm. high and 6 mm. broad. Another large specimen 

 has 23 arms 70 mm. long and the cirri 50-55 mm. long. The smallest has 12 arms 

 30 mm. long. 



One very curious individual in the Australian Museum from Port Jackson has 

 23 arms about 65 mm. long, all the IIBr series and 3 IIIBr series being developed. 

 The arms resemble those of ordinary specimens from the same locality, but the cirri 

 are most extraordinary. There are about L cirri; at the base they resemble normal 

 cirri, but most of them taper rapidly to a fine point, being only about 7 or 8 mm. 

 long; they appear as if they had all been simultaneously broken off at the base and 

 regenerated, though they are thicker at the base than regenerated cirri, a few, which 

 are broken distally, are rather longer than the majority, though much smaller than 

 normal; the longest stump is 15 mm. long. The color is a uniform slightly pinkish 

 white. 



The eight specimens from Port Jackson in the Museum of Comparative Zoology 

 (No. 298) have 11, 12, 13, 14, 15, 16, and 17 arms. One has both arms and cirri 45 

 long. All are essentially similar. 



One large specimen from Port Jackson in the U. S. National Museum has 23 

 arms. The others are smaller with 12, 14, and 18 arms. 



Carpenter's description of Antedon macronema was based upon specimens of this 

 species from Port Jackson. He said that the centrodorsal varies considerably in its 

 shape. Most commonly it is a thick disk with a smooth dorsal surface and the 

 cirrus sockets arranged irregularly on its sides, but it is sometimes more nearly 

 hemispherical, and sometimes almost columnar with the sockets disposed in vertical 

 rows (columns) of three or four each. 



The cirri are very slender and reach 45 mm. in length, the longest having nearly 

 100 segments most of which are broader than long, the middle and distal segments 

 are laterally compressed so as to overlap dorsally, and gradually develop a small 

 spine. 



The ends of the basal rays are often visible above the angles of the centrodorsal. 

 The radials are nearly oblong. The IB^ are rather longer and more convex hi the 

 center; the lower ends are united, but the outer ends are free with sharp lateral edges. 

 The IBr 2 (axillaries) are pentagonal, also much rounded in the center, with sharp 

 straight edges and small flattened sides. The postradial series may divide twice. 

 The IIBr series are 2. The elements of the IIBr series and lower brachials are 

 rounded like the elements of the IBr series, with similar straight edges and small, 



