VII. Mastigocrinus loreus. 197 
with 10 millim. 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. The plates are smooth or very 
finely shagreened, 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. 
IBB 5, pentagonal, forming a very slight angle with the 
stem. Measurements are :— 
Height. Width below. Width above. 
millim. millim. millim, 
OTOLSE UMass i5) 3 3:2 
iy baie ir ipekae ts 3 3 3:2 
In smaller specimens they are rather larger in proportion. 
BB 5; 4 are hexagonal, post.B heptagonal. Measure- 
ments :— 
Height. | Width below. Width above. 
millim. millim. millim. 
57048 B.M..... 4:5 Bus 4:25 (post.B) 
pe owdes 475 ? P(x, post. B) 
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 :— 
Width of 
Height. Width below. Width above. facet. 
millim. millim. millim, millim. 
57048 B.M..... 35 5 5 (?) 4 
Cambridge .... 4 49 4-9 31 
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 exceedingly 
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 
