242 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Notes. — There are in the collection of the Museum of Comparative Zoology 6 

 specimens of this species, 3 with 10, 1 with 11,1 with 12, and 1 with 13 arms. The 

 specimens with 11 and 12 arms are under No. 722, and that with 13 arms is under 

 No. 723. 



A 10-armed specimen from the coast of Gippsland may be thus described. The 

 centrodorsal is broad, flat, thin discoidal, pentagonal, 3 mm. in diameter. The 

 cirrus sockets are arranged in a single crowded regular marginal row. 



The cirri are XVI, 14, 8 mm. long. The first segment is very short, the second 

 is between half again and twice as broad as long, the third is usually one-third again 

 as long as broad, sometimes as much as half again as long as broad, and the fourth 

 is the longest, from half again to twice as long as broad. The fifth segment resem- 

 bles the fourth, or is very slightly shorter; it is a transition segment, with the distal 

 portion highly polished. The sixth segment is usually slightly, when at all, longer 

 than the distal width, and those following decrease in length, the outer being markedly 

 broader than long. The most highly developed cirri taper very slightly to just 

 beyond the middle of the fifth (transition) segment; in lateral view they slowly 

 broaden again from this point, as the distal segments are considerably compressed. 

 The third-fifth segments have a slight central constriction. The fifth and following 

 segments in lateral view are seen to have a minute dorsal tubercle, which at first 

 is subterminal, later becoming median. In dorsal view the dorsal process is seen to 

 broaden slowly distally, so that on the outermost segments it becomes a straight 

 median transverse ridge. The opposing spine is represented by a transverse ridge 

 with a straight crest. 



The ends of the basal rays are visible as small, low tubercles in the interradial 

 angles bridging over the exceedingly narrow subradial clefts. 



The radials are visible as narrow slightly curved bands separating the IBri from 

 the centrodorsal. The IBri are very short, about four times as broad as the median 

 length, with the proximal border convex and the distal border straight. The lateral 

 borders, which are very short, are in close apposition. The lBr2 (axillaries) are 

 sharply triangular, twice as broad as long, with all the sides nearly straight and the 

 lateral angles sharp. 



The 10 arms are 65 mm. in length. The earlier brachials have very finely 

 serrate distal ends. As the brachials become trangular the distal ends become pro- 

 duced and armed with very numerous short fine spines. In the earlier pinnules the 

 segments beyond the second have the outer edge much produced and armed with 

 conspicuous, though short, spines. These spinous crests are highest on the third 

 and fourth segments and disappear after the sixth or seventh. Besides this, the 

 entire distal border of the segments is somewhat produced and very spinous. After 

 the proximal half of the arm the crests on the earlier pinnule segments become less 

 conspicuous, but traces of those on the third and fourth segments persist to the arm 

 tips. The distal pinnules have an unusual development of small spines, and the 

 dorsal spines on the last 4 or 5 segments are unusually long and conspicuous. The 

 terminal comb consists of 6-8 teeth, beyond which is a short, smooth tip. The teeth 

 are double, being almost equally developed on each side of the segments. 



