86 
synarthry at about the 12th articulation. The angle that the syn- 
arthrial crest forms on the proximal and distal face of a joint is 
usually about 120®, but can sometimes, as in the penultimate 
segment of the stem preserved, be 0®, i. e. the crests in such cases 
Figs. 1—6. Porphyrocrinus verrucosus. 1) Upper part of the stem and the crown. 
The median arm is removed all the way from Br 2 to show the extension of 
the disk. Anal cone to the right, a regenerated arm to the left. Two pouches 
of the perisome visible, adhering to the arm from about Br 10—12, ^ji; 2) 10 
uppermost stem-joints, calyx, and Brr 1—4 of the crown, ^o/i; 3) llth—17th 
stem-joint, ^^/i; 4) 32th—35th stem-joint, e/i; 5) The two most distal stem-joints 
of the preserved stem, ®/i; 6) Proximal end of the most distal 
columnal, ®/i. 
being parallel. In one case, between columnals 33 and 34, there 
is a synostosis also in the more distal part of the stem. The dia¬ 
meter of the stem immediately below the crown is I .5 mm, 60 
mm. from the calyx the stem measures 2.6 mm, at the penultimate 
segments the broadest diameter is 3.5 mm. (— the longitudinal 
direction of the synarthry), shortest diameter (= cross section of 
the synarthry) is 2.4 mm. L. of the 10 first segments 3 mm. L. of 
the penultimate columnal 5.5 mm. The stem, which in proximal 
