216 Mr. IF’. A. Bather on British Possil Crinotds : 
For permission to examine and figure certain of the above 
specimens my thanks are due to Dr. Henry Woodward, 
¥.R.S., the Director-General of the Geological Survey, Prof. 
T, McK. Hughes, and Prof. A. H. Green ; while a double 
measure of thanks is due to Mr. Holcroft for allowing me to 
retain his specimen for several months. 
All the above specimens come from the Wenlock Lime- 
stone, and many of them come from the Upper Limestone ; 
others, however, are doubtful, and the absence of information 
srevents us from assigning them to their exact horizon. 
The trivial name of this species—derived from acinus, a 
berry, and tabus, a tube—probably refers to the blackberry- 
like appearance of the ventral sac. 
SPECIFIC DIAGNOSIS. 
Dorsal cup bow]-shaped, rather rounded at the base ;_ plates 
tumid, and smooth or shagreened. Arms rather stout, with 
rounded ossicles ; - covering-pl: ites long and conical, from 2 to 
54 to each brachial. Ventral sac large, slightly swollen 
above; its plates protuberant and rugose. Stem round, of 
moderate width, with alternate sized ossicles and a quingue- 
lobate Jumen. 
DESCRIPTION OF THE SPECIES. 
Dorsal Cup is in shape a broad cone, rounded at the base 
and often projecting radially. The shape, though charac- 
teristic (PI. XIII. figs. 4, 5), is very variable in minor points. 
Thus, the infrabasals may project at a rather sharp angle 
with the stem-axis, or may gently curve upwards. The 
plates, especially the basals, may be very tumid (PI. PSU 
fi. 2); but im a few cases the swelling is inconspicuous. 
The projection of the radials also varies very much, as seen 
by comparing fig. 1 with fig.4 in Pl. XH. The cup some- 
times varies on different sides both in height and in the sizes of 
its plates, the anterior rays as a rule being the larger in such 
cases. ‘The average measurements of the cup, as deduced 
from five specimens, after corrections have been made for 
compression, are:—Height 13 millim.; width below, 69 
millim. 3 width above, 14°8 millim. Extremes of height noted 
are, in 57365.B.M. 7-2 millim., and in E 6003 B.M. 20 
millim. In these and subsequent measurements no account 
is taken of the young specimen at Jermyn Street or of those 
in the W Bearish “Museum. 
1 BB 5, pentagonal and, as a rule, almost equal-sided. 
