216 ]\Ir. Y. A. Batlicr on British Fossil Crinoids : 



For permission to examine and figure certain of tlie above 

 specimens my thanks are due to Dr. Henry Woodward, 

 F.R.S., the Director-General of the Geological Survey, Prof. 

 T. WK. Hughes, and Prof. A. H. Green ; while a double 

 measnre of thanks is due to Mr. Holcroft for allowing me to 

 rttain his sjiecimen for several months. 



All the above specimens come from the Wcnlock Lime- 

 stone, and many of them come from the Up])er Limestone ; 

 others, however, are doubtful, and the absence of information 

 prevents us from assigning them to their exact horizon. 



The trivial name of this species — derived from acinus, a 

 berry, and iuhiis, a tube — probably refers to the blackberry- 

 like appearance of the ventral sac. 



Specific Diagnosis. 



Dorsal cnp.bowl-shaped, rather rounded at tlie base ; plates 

 tumid, and smooth or shagreened. Arms rather stout, with 

 rounded ossicles ; covering-plates long and conical, from 2 to 

 3| to each brachial. Ventral sac large, slightly swollen 

 above ; its ])lates jootubcrant and rugose. Stem round, of 

 moderate width, with alternate sized ossicles and a quinque- 

 lobate lumen. 



Desckiptiox of the Sfecies. 



Dorsal Clip is in shape a broad cone, rounded at the base 

 and often jMojecting radially. The sha))e, though charac- 

 teristic (PI. XIIL figs. 4, 5), is very variable in minor points. 

 ■Jhus, the infiabasals may project at a rather sharp angle 

 with the stem-axis, or may gently curve upwards. The 

 ])latcs, especially the basals, may be very tumid (1*1. XI II. 

 fig. 2) ; but in 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 PI. XIII. The cup some- 

 times varies on diflferent 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 lor 

 com])ression, are: — Height 13 niillim. ; width below, 6"9 

 millim. ; width above, 14*8 millim. Extremes of heii^ht noted 

 are, in 57365 P.M. 7*2 millim., and in E 6003 P.M. 20 

 millim. In these and subsequent measurements no account 

 is taken of the young specimen at Jermyn Street or of tho?5e 

 in the ^^'oodwardian ^fuseum. 



1 p]j b, pentagonal and, as a rule, almost equal-sided. 



