MONOGRAPH OF THE EXISTING CRINOIDS. 55 



The muscular fossae are nearly or quite half again as broad as high, sub- 

 quadrangular, with broadly rounded distal corners and distal edge. There is a 

 very narrow, but very deep, intermuscular notch which reaches downward for 

 about half the distance from the distal edge of the muscular fossae to the distal 

 edge of the central canal. This notch is rounded proximally and is always more 

 or less obscured by the closing together of the muscular fossae over it. 



The joint face elements distal to the transverse ridge slope inward, at first 

 making an angle of about 45 with the plane passing through the middle of the 

 joint face and including the dorsoventral axis of the animal, but they gradually 

 curve around and at the middle of the joint face are parallel to the transverse 

 ridge, so that the inner portion of the joint face, instead of being a reentrant right 

 angle, is broadly rounded. This also results in a considerable shortening of the 

 distance of incision of the reentrant angles of the stellate border of the ventral 

 surface of the radial pentagon. 



There is scarcely more than a trace of calcareous deposit within the ventral 

 surface of the radial pentagon. 



Diameter of radial pentagon at base, 5 mm. ; height of articular face (meas- 

 ured along the inclination), 2.7 mm.; width, at transverse ridge, 3.8 mm.; distance 

 from center of rosette to middle of dorsal outer edge of radial, 2.1 mm. ; diameter 

 of ventral interarticular space, 1.9 mm. 



COCCOMETRA HAGENII. 

 Figs. 112, 113, p. 67. 



The dorsal ligament fossa is about three times as broad as long, with the 

 proximal border semielliptical. Only that part of the ligament pit just under the 

 transverse ridge is indicated; this is very narrow, somewhat broader than the 

 central canal. 



The ends of the transverse ridges just join over the interradial planes, but the 

 dorsal ligament fossae are entirely free laterally. The interarticular ligament fossae 

 are laterally separated by a moderately deep narrowly V-shaped furrow, which is 

 almost or quite bridged over by the distal half of the muscular fossae. 



The interarticular ligament fossae are rather deeply excavated and are prac- 

 tically equilateral triangles with their inner angles truncated by the rim about the 

 central canal. The distal border is slightly convex. 



The intermuscular ridge is high and broad proximally, but decreases rather 

 rapidly in height and breadth in the proximal third, more gradually from that 

 point onward. 



The muscular fossae are narrow and high, rounded triangular. Their height 

 is somewhat over twice their maximum width, and about the same as the height 

 of the interarticular ligament and dorsal ligament fossae combined. Their outer 

 edge has practically the same direction as the outer edge of the interarticular 

 ligament fossae. 



There is no calcareous deposit within the ventral surface of the radial pentagon. 



142140 21 Bull. 82 6 



