502 BULLKTI.V 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



The 10 arms are probably about 60 ram. long. The first bracliials have long 

 exterior borders. The second brachials are irregularly quadrate and rise posteriorly 

 to a synarthrial tubercle with the first. The following brachials are triangular, broader 

 than long. The widtli at the first syzygy is 1.5 mm. and the length from the pro.ximal 

 edge of the IBri to the second syzygy is 7.0 mm. 



Syzygies occur between brachials 3+4, 9 + 10, and 14+15, and distally at intervals 

 of from 3 to 7 (usually 4) muscular articulations. 



Pi and P» are absent. 



Pj is 7 mm. long with 15 segments. P3 and Pc are generally stouter, and those 

 following less so, but of increasing length. 



The disk is naked, about 6 mm. in diameter. 



The color in alcohol is a deep rose red with the cirri and the ends of the arms white. 



Description oj the type o/B. elongata. — The centrodorsal is sharply conical, greatly 

 elongated, 1.5 mm. broad at the base and 4 mm. high, with the sides divided into 5 

 radial areas by shallow U-shaped furrows averaging about half as broad as the adjacent 

 cirrus sockets. In each radial area there is a median line rather less than half as 

 broad as the interradial furrows. Each radial area carries 2 columns of cirrus sockets, 

 one on either side of the median line, of 4 or 5 each, beyond which, in the apical third of 

 the centrodorsal, are several partially obliterated sockets continuing the columns. 



The cirri are XLV, 27-35 (usually nearer the latter), from 20 to 26 mm. long. 

 The first segment is about twice as broad as long, the second is shghtly longer than 

 broad, the third is about two and a half times as long as broad, the fourth is rather over 

 three times as long as broad, and the fifth and following are about four times as long as 

 broad, or rather longer; after the tenth or twelfth the segments gradually decrease in 

 length so that the last ten are about as long as broad or only slightly longer than broad. 

 After the fii'st ten the distal dorsal edge of the segments begins to be somewhat prom- 

 inent, this feature very gradually increasing distally. The opposing spine rises from 

 almost the entire dorsal surface of the penultimate segment; it is rather stout, ^rith 

 the ape.x terminal in position, and its height is somewhat less than the width of the 

 segment which bears it. The terminal claw is moderately stout and moderately curved, 

 and about as long as the penultimate segment. 



The radials are rather long, about t\vice as broad as long in the median line. The 

 IBri are over twice as broad as their lateral length vnth shghtly converging sides, which 

 are not in contact basally, and with the distal border concave. The IBr2 (axillaries) 

 arc rhombic, about as long as broad. 



The 10 arms are all broken off near the base. The first brachials are small, about 

 3 times as long exteriorly as interiorly, not in contact interiorly, with the distal border 

 concave. The second brachials are much larger, irregularly quadrate. The first 

 syzygial pair (composed of the third and fourth brachials) is half again as long interiorly 

 as exteriorly, and about twice as broad as the exterior length. The following brachials 

 as far as the second syzygy are slightly wedge-shaped, about twice as broad as long. 



Pi and Pa are absent. 



The color in alcohol is purple, the pinnules and cirri and a broad median band on 

 the arms white. 



Notes. — -The differences between the type of balanoides and the type of elongata 

 may be summarized as follows: 



