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BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLDME 1 



Figure 13. — Peripheral cirri of: a, Antedon petasus (Duben and Koren); b, A. bifida (Pennant); 

 c, A. bifida moroccana A. H. Clark; d, A. hupferi Hartlaub; e, A. mediurranea (Lamarck). 

 /, Division scries and first brachials of A. viediterranea; g and h, same of A. bifida, small and 

 large. (The arrows on b and c indicate the measurements taken.) 



Sj'zygies occur between tlio third and fourth, ninth and tenth, and fourteenth and 

 fifteenth brachials and distally at intervals of three muscular articulations. 



There are about 35 pairs of pinnules. Pj is from 12 to 15 mm. long, composed of 

 from 30 to 45 (most commonly about 35, rarely over 40) segments of wliich the first is 

 not quite so long as broad and the remainder are fairly uniform, about half again as long 

 as broad; it is much stouter basally than Pj and tapers gradually to a delicate and 

 flagellate tip. Pj is about half as long as P,, or verj- slightly longer, and much less stout, 

 composed of from 20 to 25 (usually about 20) segments of which the first is about as 



