198 Mr. F. A. Bather on British Fossil Crinoids : 



irregular and numerous, as in Botryocrinus, but appear to be 

 more or less alternating (zincotype, figs. 3 and 4), 



The total length of the arms in 57048 B.M. is 11 centira. 



I Br number from 7 to 11, the usual number being 8. 

 Their height is 1*4 millim. ; their width 3 millim, 



II Br 9, 10, or 11. 



III Br from 9 to 14. 



IV Br from 12 to 26. 



V Br numbers noted 17 and 22. 



VI Br numbers noted 16 and 25. 



VII Br 15 observed. 



VIII Br and IX Br are so small 

 and faint that it is difficult to make 

 out tiieir exact numbers, Tiie 

 Avidth of the finials is about "Id 

 millim. Tlie distal portions of 

 an arm-branch are figured here 

 (fig. 6), to show that there is no 

 suspicion of pinnules. 



Anal structures. — Anal x is 

 hexagonal, resting on the hori- 

 zontal upper side of post. B, in 

 a line with RR, and supporting 

 three plates, viz. a median proxi- 

 mal plate of similar shape and 



a small plate on either side be- t^- n ir ; i-k- *. i j <• 



. r I"ig- 9- — Jl. loreus. Distal end of 



tween it and the adjacent radiais p^rt of 1. post. Arm in o704S 

 {rt and If) . B. M. ( X 6j diam.) 



The Ventral Sac in 57048, 

 where it is magnificently displayed, has a length of 7 

 centim. At its origin it is 10 millim. wide, but rapidly 

 increases to 13 millim. and then decreases very gradually. It 

 is transversely compressed and is very fiat. 



In its plan of structure this sac resembles those of Thenaro- 

 crinuSj Botryocrinus^ and Dendrocrinus (what may be called 

 the wickerwork-type, Trautschold's "Angulosi"). Seen 

 from the posterior, 5 ridges are visible, which are from left to 

 right as follows : — (1) ridge starting from It, (2) ridL;:e starting 

 from a plate intercalated between It and median proximal 

 plate, (.i) median ridge, starting from median proximal plate, 

 (4) ridge starting from W, (5) ridge ou riglit of rt ridge. 

 There are probably three other ridges on the anterior side. 

 This would make the number of ridges 8 in all, in which the 

 genus would agree with llienarocrinus if not with others of 

 the group. 



The ossicles are slightly ridged in the middle, and are 



