A MONOGRAPH OF THE EXISTING CRINOIDS 211 



are slightly longer again. The dorsal surface of the segments in the outer half of the 

 cirri is faintly subcarinate. The penultimate segment is nearly or quite half again as 

 long as broad, slightly narrower than the segment preceding, with the dorsal and ven- 

 tral profiles parallel. The opposing spine is terminal, directed obliquely forward, 

 and forked. The terminal claw is about as long as the penultimate segment, rather 

 stout basally and moderately curved. 



The ends of the basal rays are visible as large rhombic tubercles in the interradial 

 angles, which almost or quite separate the radials. The radials are concealed except 

 for the distal border, which is much swollen and forms a chevron-shaped band just 

 above the margin of the centrodorsal, which has a slight tubercular swelling in the 

 middle, and sometimes another on either side of this. The IBri are extremely short, 

 forming a swollen chevron-shaped band similar to that formed by the radials, but 

 somewhat wider. The center of this band is swollen into a broad low tubercle, and the 

 lateral ends are abruptly produced and sometimes swollen, meeting those of the ad- 

 jacent IBr t . The lateral distal angles are rounded. The IBr 2 (axillaries) are rhom- 

 bic, twice as broad as long. The proximal half is raised into a broad well-rounded 

 tubercle. Below the lateral angles there is a flangelike proximal extension which 

 meets the distal border of the IBr t . As a result of this, the axillaries are seen to have 

 straight lateral borders, meeting those of the neighboring axillaries, which are about 

 as long as the sides of the IBr^ The IIBr series are 2. 



The 10-13 arms are 190 mm. long. The first brachials are half again as long 

 exteriorly as interiorly, four times as broad as the median length; the proximal and 

 distal edges are parallel from the inner border as far as the median line, where the distal 

 edge runs at an angle to the proximal edge to the outer distal angle. The inner distal 

 angle is somewhat produced and broadly rounded, slightly overlapping the adjacent 

 portion of the second brachial. The second brachials are about twice as large as the 

 first, almost twice as long exteriorly as interiorly. The proximal border is in the form 

 of an obtuse angle with the apex in the median line. The first syzygial pair (composed 

 of brachials 3 + 4) is oblong, three times as broad as long; the dorsal surface of both the 

 hypozygal and epizygal is swollen, so that the syzygial line lies in a groove between 

 them. The next 10 brachials are oblong or slightly wedge-shaped, about four times as 

 broad as the median length. The middle of the dorsal surface is raised into a high 

 ridge distal to which the surface slopes evenly to the distal border, while proximally it 

 drops almost or quite perpendicularly to the longitudinal axis of the arm, so that 

 proximally the ridge is bordered by a narrow portion of the surface of the brachial 

 which is parallel with the longitudinal axis of the arm. Beyond the tenth brachial the 

 portion of the surface distal to the ridge becomes hollowed so that the ridge becomes 

 narrower and more conspicuous. On the earlier triangular brachials the ridge is strongly 

 and regularly curved, passing from the distal end of the shorter side inward and down- 

 ward through the proximal third of the median line and upward and outward to near 

 the distal end of the longer side. Soon the ridge becomes angular, the apex of the angle 

 being in the middle of the median line. It then moves distally and soon comes to 

 coincide with the distal border of the brachials, where it disappears. On the triangular 

 brachials the midline proximal to the angle of the ridge is raised into a rounded keel. 

 As the ridge moves distally and disappears this median keel becomes narrower and more 

 prominent, though always very low and rounded, and persists to the arm tips. 



