498 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



has 41 arms. The postradial series are rather widely separated. The cirri have 25-28 

 segments, of which the distal are strongly carinate in the middorsal line. P 2 is very 

 long on the outer arms of each postradial series and may have 30 segments. It is 

 stout basally, but becomes flagellate distally. 



The specimen from Caspar Strait was described by Hartlaub as a new species 

 under the name of Antedon subtilis. According to him the centrodorsal is flat discoidal, 

 with the cirri arranged mostly in two rows. The cirri are about XX, about 20, about 

 12 mm. long. They are moderately slender, and are laterally compressed in the outer 

 half. From the fifth onward the segments are somewhat elongated. The distal 

 segments have a very feeble dorsal spine, and the antepenultimate a stronger spine. 

 The radials are partially visible at their sides. The IBr t are short, somewhat shorter 

 than the sides of the pentagonal axillaries. The IIBr and IIIBr series are 2. There 

 are no IVBr series. The IIBrj and IIIBrj are about as long as the sides of the IBr, 

 and IBr 2 together. The postradial series are entirely free from the radials onward. 

 The ossicles of the division series and the brachials are entirely smooth. There are 

 no synarthrial or articular tubercles. The 20 arms are 52.5 mm. long. One of the 

 postradial series bears five arms, one three, and the other three four each. The arms 

 are moderately slender, entirely smooth, and provided with very slender pinnules. 

 The brachials are short and as far as the eighth are more or less discoidal, becoming 

 markedly triangular from the ninth onward and so remaining until about the twentieth 

 when they become more trapezoidal and later squarish. The first brachials are hi 

 partial contact interiorly. The first syzygy is between brachials 3+4, the second is 

 between brachials 15 + 16, and the third is separated from the second by 6 or 7 mus- 

 cular articulations. The distal intersyzygial interval is 7 or 8 muscular articulations. 

 P! is about 7 mm. long and is composed of about 13 smooth segments, which with the 

 exception of the two basal are elongated. P 2 is 10 mm. long, markedly stouter than 

 P 1( and flagellate; as in Pj the segments are elongated with the exception of the two 

 first. The three following pinnules on the same side of the arm are very diminutive, 

 and are only about 2 mm. long. The length of the pinnules then gradually increases, 

 the pinnules of the middle portion of the arms remaining, however, small and slender. 

 The pinnules of the arm tips are of a hairlike fineness, but somewhat longer (5 mm.) ; 

 the segments are always elongated. The disk is deeply incised. Sacculi are abundant 

 and closely set. The color in alcohol is uniform white. 



Hartlaub said that subtilis is nearly allied to Lamprometra klunzingeri (see page 

 527) but differs from it in the smallness of P 3 , which in klunzingeri is as long as P!. He 

 remarked that after a study of more material the two forms may be found to be 

 identical. 



The details of the specimens from Siboga station 78 are as follows: One has 21 

 arms 75 mm. long; P 2 on the outer arms is very large; all the proximal pinnules are 

 considerably enlarged. A second has 21 arms 70 mm. long; P 2 is greatly enlarged on 

 the outermost arms of each postradial series, where it stands out with great prominence. 

 The others are similar; one has 26 arms, two have 25, and one has 22. The remaining 

 three specimens are small. 



One of the specimens from Siboga station 796 has 28 arms about 60 mm. long. 

 The other is smaller. 



