VII. Mastigocrinus loreus. 197 



with 10 inillini. of stem, and" it shows the delicate finials very 

 well. It is on a large block of limestone, and comes from 

 the Fletcher collection. 



Dorsal cup conical, .slightly expanding above, much as in 

 Botryocrinus decadactylus. Tiie plates are smooth or very 

 finely shagrcened, and almost plane. Measurements are : — 

 Height along posterior interradius, 10 millim. ; width below, 

 5*2 millim. ; width above, 14 millim., but some of this is due 

 to crushing. 



I15B o, pentagonal, forming a very slight angle with tiie 

 stem. Measurements are : — 



Ileig^ht. Width below. Width above, 

 millim. millim. millim. 



67048 B.M 3-5 3 32 



3 3 3-2 



In smaller specimens they are rather larger in proportion. 



BB 5 ; 4 are hexagonal, post.B heptagonal. Measure- 

 ments : — 



In smaller specimens they are rather larger in proportion. 



RR 5, of normal shape ; bending outwards towards the 

 facet and curving inwards towards the radial processes, as in 

 Botryocrinus. Measurements are : — 



The articular facet (zincotype, fig. 1) has a very faint trans- 

 verse ridge and the axial canal is not separate. 



The Arms are about 11 times as long as the height of the 

 cup ; they dichotomize at least 8 times, at rather long 

 intervals, and decrease very gradually both in the diameter and 

 height of the ossicles. All this gives them an exceedino-ly 

 slender and graceful appearance, especially when they have a 

 delicate wave as in 57048 B.M. Corresponding branches are 

 equal in size, except perhaps occasionally in the extreme 

 distal region, where one branch sometimes appears to be 

 smaller than its fellow. 



The ventral groove is a slight wide depression, from which 

 a narrow V stretches to the axial canal which is not sepa- 

 rated by stereom (zincotype, fig. 2). The covering-plates are 



