British Fossil Crinoids. 251 



IBB 3, two large and one, the r. post., small. Height of 

 r. post. IB, 3'9 mm. Stem-facet circular, not clearly seen ; 

 diameter, circa 1"5 mm. The facet slopes in accordance 

 Avith the general asymmetry of the theca. Aiistin^s fig. 2 a 

 shows a minute lumen and a finely ridged border. 



B13 5 : l.ant. and r. post, hexagonal; in post. B the upper 

 angle is truncated by the periproct; in 1. post, and r. ant. BB 

 the lower margins meet in a curve, making the plates penta- 

 gonal. Post. B is the largest, its height and width being 

 4"7 and 4"55 mm. ; r. ant. B is the smallest, its height and 

 width being 4"3 and 3 mm. 



IIR 5, in general form more or less shield-shaped, but 

 variously modified ai.d unequal in size. The largest is 

 1. post. R, Avhich projects upwards higher than the others, 

 M'ith its shoulders sloping up to a truncated flattenc d 

 surface, which may be au arm-facet ; on its right side this 

 radial is excavated below by the periproct. Next in size are 

 1. ant. R, which slopes up to 1. post. 11, and r. post. 11. The 

 latter on its left side is excavated below by the periproct, 

 and is produced above so as to arch over the periproct; in 

 this region eitlier it meets 1. post. R or is separated from that 

 plate by a small anal plate ; I rather incline to the latter 

 interpretation, but the evidence is none too clear. The 

 remaining radials, r. ant. R and ant. R, were still smaller ; 

 r. ant. R is broken away, but its outline can be reconstructed ; 

 it was probably the smallest of the five. Thus, in accordance 

 with the general asymmetry, there is a slope of the up[)er 

 surfaces of the radials, down from the projecting 1, post. R to 

 r. ant. IR. 



The brachial facets cannot be distinguished, but, as seen 

 from above (tig. 1 />*), the radials bound a rather irregular 

 opening, to which an angular excavation of the up[)er margins 

 of the radials tends to give a pentagonal character. Whether 

 in the living state this was covered by orals, tegminals, or 

 reduced brachials is uncertain ; at any rate it was uncovered 

 in all the fossils known to the Austins, and this fact no 

 doubt it was tliat suggested the trivial name unapeptainenas 

 (lying open), in distinction to clansus. 



In considering the Relations of Sycocrinus anapepta- 

 menus, it is seen at once that they are very close to 

 " Hypocrinus" piriformis, and thus far my former suggested 

 reference of this British species to Hypocrhms is confirmed. 

 I have, however, recently shown that H. piriformis is no 

 Hypocrinus but a Taxocrinid (Proc Zool. Soc. 1913, p. 910). 

 The difference between it and S. anapepiainenus lies Cfsenli- 

 ally in the greater size of the right posterior radial in the 



