66 Proceedings of the Biological Society of Washington. 



is very short, the second squarish or slightly longer than broad, the third 

 from half again to nearly twice as long as its proximal diameter, the fourth 

 the longest, twice as long as its proximal diameter or somewhat longer; the 

 fifth is as long as the third, and the following gradually decrease in length 

 to the antepenultimate, which is about as long as broad ; the penultimate 

 segment is somewhat longer ventrally than dorsally, one-third to one-half 

 again as broad as its ventral length; the opposing spine is small, erect, 

 arising from the whole dorsal surface of the penultimate segment, the 

 apex slightly beyond the center of the latter; the terminal claw is long 

 and slender, about three-quarters of the length of the penultimate and 

 antepenultimate segments together, moderately curved; the second and 

 following segments as far as the terminal three or four are very strongly 

 constricted centrally as viewed dorsally, with much expanded articula- 

 tions; but this character is only slightly marked in lateral view, being due 

 to the lateral expansion of the articulations over the ends of the articu- 

 lating ridges as a center; most of the segments are smooth dorsally, but 

 the antepenultimate always, the preceding often, and the one preceding 

 that sometimes, has a small subterminal tubercle or small spine which, 

 though often but slightly marked, is always present; its position on the 

 antepenultimate segment is but little in advance of the center, on the 

 preceding more distal, and on the third from the last it is situated near 

 the distal border. 



The ends of the basal rays are visible as small tubercles in the angles 

 of the calyx; the radials are concealed in the median line, showing 

 slightly in the angles of the calyx; the IBr x are oblong, with the proxi- 

 mal border often convex, about two and one-half times as broad as the 

 median length, rounded laterally and entirely separated, even at the 

 base; the I Br 2 (axilaries) are almost triangular, between one and one- 

 half times and twice as broad as long, the anterior angle sharp, though 

 not produced, the lateral sides short, forming an obtuse angle with those 

 of the IBrj, or parallel in the proximal half but diverging in the distal; 

 II Br 4 (3 + 4); division series comparatively slender and widely sepa- 

 rated; first ossicles following each axillary united interiorly for about the 

 proximal two-thirds, those following the I Br axillary then diverging at 

 an acute angle, those after the II Br axillary remaining in apposition in 

 the distal third, though not united. 



Sixteen to twenty very slender arms about 150 mm. long; the first 

 brachial is wedge-shaped, about twice as broad as the exterior length; 

 the second is similar in shape and size; on arms springing from a II Br 

 axillary the first brachial is much larger, being not greatly broader than 

 the exterior length ; first syzygial pair (on arms arising from the II Br 

 axillaries composed of the second and third brachials, on those arising 

 from the I Br axillaries of the third and fourth) oblong, about half again 

 as broad as long, or slightly broader; following three brachials (follow- 

 ing one or two on arms springing from a II Br axillary) oblong, about 

 twice as broad as long, then becoming very obliquely wedge-shaped, 

 about as long as broad, in the distal part of the arm less obliquely wedge- 

 shaped, almost oblong, about as long as broad, and in the attenuated 



