﻿REPORT OF THE DIRECTOR IQIO 



239 



small depressions, one on either side of the suture. A portion of the 

 plate between a pit and the suture is distinctly raised. Plate 5 figure 

 4 shows a pair of these near the lower end of the suture between 

 r.ant.R and r.post.R. They are suggestive of end openings to young- 

 canals, but they are difficult structures to photograph and will also 

 be dismissed with this brief notice of their presence. 



Lateral extension of the theca. Text figures 5 and 6 show a 

 somewhat marked antero-posterior flattening of the species that is 

 but very slightly due to compression by overlying deposits. Text 

 figure 19 shows a view of the proximal ends of the IBB and the im- 



r.posUB. 



B.ntJB'. 



6S° 



Fig. 19 Proximal end of Palaeocrinus striatus Billings. From a photomicrograph xio. 



The angles indicated are those of the ends of the sutures nearest the proximal columnal. The 

 [ figure shows clearly the five depressions due to inhibition of stereom formation on the lateral 

 [_ sutures of the IBB. This is most pronounced opposite the oldest portions of these plates. The 



r. post. IB carries a good cast of one of the sutures of the proximal columnal. 



print of the proximal stem joint, which in two places clearly shows 

 the imprints of its sutures. There is no evidence for a pentagonal 

 column. The flattening of the theca is manifest even here and the 

 first columnal was an oval and not a circle. On extending the 

 sutures shown in this figure and measuring the angles between them, 

 it will be seen that 1. post. IB and r. post. IB together take up 158 of 

 the posterior side of the column, or 14 more than their share. There 

 can be no question here but that we are dealing with differences due 

 to growth. The 1. ant. IB came on one edge of the fold and is the 



