256 THE VOYAGE OF H.M.S. CHALLENGER. 



3. Antedon variipinna, Carpenter (PI. XXXVI. figs. 1-6; PI. XLVIII. figs. 3-5; 

 PI. XLIX. figs. 1, 2). 



Specific formula — A.[3.(2)].-r-. 



1882. Antedon variipinna, P '. H. Carpenter, Journ. Linn. Soc. Lond. (Zool), 1882, vol. svi. 



p. 506. 

 1882. Antedon erenulata, P. H. Carpenter, Ibid., p. 507. 

 1882. Antedon decipiens, Bell, Proc. Zool. Soc. Lond., 1882, p. 534. 

 1882. Antedon irregidaris, Bell, Ibid., p. 534. 

 1882. Antedon decipiens, P. H. Carpenter, Ibid., p. 746. 

 1882. Antedon erenulata, P. H. Carpenter, Ibid., p. 746. 

 1882. Antedon irregularis, P. H. Carpenter, Ibid., p. 746. 

 1882. Antedon variipinna, P. H. Carpenter, Ibid., p. 746. 

 1884. Antedon decipiens, Bell, Bep. Zool. Coll. H.M.S. "Alert," Lond., 1884, p. 159, pi. xi. 



figs. B, a. 

 1884. Antedon irregidaris, Bell, Ibid., p. 161, pi. xiii. figs. A, a-c. 



Centro-dorsal a low and slightly convex disk, bearing from fifteen to thirty cirri on 

 its sides. They have twenty to thirty-five joints, some of the lower ones being longer 

 than wide. The later joints are usually somewhat compressed laterally and rather 

 sharply carinate in consequence, but they sometimes bear well-marked spines. 



The first radials are never altogether invisible in a side view, and are often com- 

 paratively large and granulated externally. The second are short, wide, and laterally 

 united, forming more or less of a prominence at the middle of their junction with 

 the broadly pentagonal axillaries. The rays generally divide twice and sometimes three 

 times, the distichal series consisting of three joints, the axillary with a syzygy, and the 

 palmars (when present) of two joints, the axillary without a syzygy. The dorsal surface 

 of these radial, distichal. and palmar joints is often considerably arched. 



The arms vary in number from eleven (probably even ten) to twenty-five or more, 

 and may have one hundred and eighty joints. The first six or eight brachials are 

 relatively short and wide, nearly oblong in outline, and often much rounded dorsally. 



The following joints are more triangular, with a variable tendency to overlap dorsally, 

 and their broader ends project alternately on opposite sides of the arm to a greater or 

 less extent. Further out they become more quadrate again, but remain relatively short 

 and wide and more or less overlapping till almost the very end of the arm. A syzygy in 

 the third brachial, and the next between the tenth and fifteenth, w T ith others at intervals 

 of six to twelve joints, usually nine or ten. 



The first pinnules are comparatively small, and consist of about twenty short joints, 

 the lowest of which are broad and slightly carinate. The distichal pinnule (if present) is 

 smaller than that on the second brachial, and so is that on the third brachial. The 

 following pinnules may reach nearly 15 mm. in length, with as many as twenty-five 

 joints, which are both longer and stouter than in the lower pinnules. The relative sizes 



