402 Dr. F. A. Bather on British Fossil Crinoids : 
The Diameter varies from 3 mm. (57542e) to 6-4 mm. 
(57541) ; in general it is about two-thirds that of B. di- 
dactylus. 
The Side-Faces in all specimens appear smooth, but the 
state of preservation is such that the original surface has 
often been destroyed or coated over, so that minute granules 
may have occurred in some stems. The surface is also 
plane or equable as a rule, but various specimens show slight 
swellings either about the equator of the columnal (cf. Forbes, 
fig. 9) or near each margin; occasionally there are irregu- 
larities suggestive of the granules that border the radi in 
some specimens of B. didactylus. There are, however, no 
such marked ridgings as occur in that species. Some 
specimens have radial pores well marked (Sowerby, fig. 3a ; 
Forbes, fig. 8), others appear to be entirely without them ; 
but there are intervening gradations. 
The Number of Internodals varies from 14 in 57541, 
which is from a proximal region (vide infra), to over 29 in 
the two smooth specimens under 57551. 
The internodals of smooth forms are equal in height, but 
the syzygial ossicles are usually lower in adult stages. The 
following are some measuremeuts in millimetres :— 
57542 e. 57542 ¢. E5638 a. 57543. 57540. 57843 d. 57543 b, 
Diameter .... 3°0 37 46 ofl." ore 56 59 
Height of inter- 
HOGI Ae ie Li, Lg 2:1 1:9 19 16 21 
Height of epi- 
BY > plese 3 15 sas 2°0 2:0 1:8 13 23 
Alternation in Height of internodals is more frequent in 
the quinquelobate or substellate fragments, which no doubt 
come from more proximal regions of the stem. It is 
usually accompanied by a slight increase in the diameter of 
the ossicle. In 57542 a, with mean diameter about 3°5 mm., 
internodals of 1:°2 mm. are interspersed with others of 
1:0 mm. in height; the epizygal is 1°35; the hypozygal 
10 mm. In 575426, with diameter 4°2 mm., the inter- 
nodals are arranged thus : 
14/18 /1:4/2:1/14/1:4/1:8/1:4/1:8/ 
In 57543a, with diameter 5:0 mm., the height of inter- 
nodals varies between 2°0 and 1'7, the epizygal being 
1:38 mm. In 57541, with diameter 6°1 mm., wnsls walle 
marked rounded stellate section, there are two epizygals 
(Order I), each about 1°5 mm. high; between these are 
turee internodals of about 1°3 mm. (Order II), separated 
from each other and from the epizygals by 3 internodals of 
