348 BULLETIN 82, UNITED STATES NATIONAL MUSKi U 



processes on the preceding Begmente. It is triangular, arising from the entire dorsal 

 surface of the penultimate segment; the anterior profile is straight or very slightly 

 concave and strongly oblique, and the distal profile is straight, very slightly convex, 

 or s cry slightly coiieav e, and forms almost a straight line with the distal edge of the 

 penultimate segment. The height of the opposing spine is equal to about half the 

 width of the penultimate segment. The terminal claw is half again as long as the 

 penultimate segment or somewhat shorter, rather slender, and moderately and evenly 

 curved. 



The distal ends of the radials arc visible beyond the rim of the centrodorsal. 

 They may form a very narrow band of approximately equal width throughout, or they 

 m.i v be almost wholly concealed by the centrodorsal in the median line. The IBr, 

 are very short, about six times as broad as long, with the proximal and distal edges 

 parallel if viewed at right angles to the dorsal surface. The anterolateral angles are 

 more or less broadly rounded off, and the lateral edges are narrowly swollen. They 

 are in lateral apposition as far as the rounded anterolateral angles. The IBr 2 (axil- 

 laries) are triangular, with the lateral angles slightly truncated, twice as broad as 

 long, with the anterior borders only very slightly concave. The truncated lateral 



is arc very slightly and narrowly thickened and are in lateral apposition. There 

 is a very prominent, though not produced, synarthrial tubercle on the articulation 

 between the elements of the IBr series. The sides of the elements of the IBr series 

 and of the first two brachials as far as the base of Pi are sharply flattened, and the 

 dorsolateral edge is slightly and narrowly everted or swollen. 



The 10 arms are 200 mm. long. The first brachials are wedge-shaped, half again 

 as long exteriorly as interiorly, united interiorly for almost their entire length. The 

 second brachials are somewhat larger and are much more obliquely wedge-shaped. 

 The first syzygial pair (composed of brachials 3 + 4) is oblong and exceedingly short. 

 The next six or seven brachials are almost oblong, about five times as broad as long, 

 and those succeeding become very obliquely wedge-shaped, almost triangular, about 

 three times as broad as the length of their longer side. Later the brachials slowly 

 become less and less obliquely wedge-shaped so that after the proximal third of the 

 arm the brachials are oblong, very short, about 5 times as broad as long, becoming 

 slowly somewhat longer toward the arm tip. 



The first syzygy is between brachials 3+4, the second most frequently between 

 brachials + 10, and the third usually between brachials 16+17. The second syzygy 

 is often between brachials 10 + 11, and it may be as late as between brachials 28 + 29. 

 The distal intersyzygial interval varies from 10 to 60, but is usually between 10 and 

 16, muscular articulations. 



Pi is 11 -12 mm. long and is composed of 25 segments. It is slender and flexible, 

 tapering evenly in the proximal half and becoming flagellate and flexible in the distal 

 half. The first segment is about as long as broad, the second is slightly longer than 

 broad, and those following slowly increase in length to the eighth which, with the 



linder, is from one-third to one-half again as long as broad. The second-fourth 

 and proximal part of the fifth segments have the side toward the arm tip sharply 

 rounded off, though not produced. P 2 is 14 mm. long, with 20-22 segments, much 

 stouter than I', and tapering slowly and evenly to the tip. The first two segments are 

 slightly broader than long, the third is almost as long as broad, the fourth is very 



