SAGENOCRINIDAE 205 



Family SAGENOCRINIDAE Roemer, emend. Springer 



Sagenocrinoidea with infrabasals more or less recumbent, taking little part in the 



calyx wall. crown usually elongate. rays above radials 



partly or wholly separated 



Analysis of the Genera 



I. RA in form of R, under r. post. R. 



Anals and iBr chiefly in lower part of areas, followed by perisome. 

 Arms dichotomous. 



Anals more than one abreast.. IBr 2 Temnocrinus. 



Anal x followed by others in series tending to form a tube. IBr 3 . . Meristocrinus. 

 II. RA obliquely to left of r. post. R, not touching r. ant. R, usually between BB. 

 Anal and iBr areas filled with solid plates in more than one series. 



Arms dichotomous. IBr 2 Sagenocrinus. 



III. RA only in upper oblique position. 



Anals and iBr well developed in lower part of areas, passing into 



perisome. IBr 2 Lithocrinus. 



Arms heterotomous. 10 main trunks with ramules. 

 Anals and iBr variable ; may be only a few in lower part, followed 

 by perisome, or numerous, filling areas with solid plates. 

 Arms dichotomous. 



Post. B longer than others. IBr 3 (exceptionally 2) Forbesiocrinus. 



This family partakes in a smaller degree of the infrabasal character of the 

 Lecanocrinidae — those plates, while taking a small part in the calyx wall, being 

 to a variable degree recumbent, and reaching the outer surface by a rather nar- 

 row rim or wedge-form extension from the interior. It is in general charac- 

 terized by a large, elongate and spreading crown, with rays not in contact, and 

 with arms more or less divergent. Only in young specimens of Forbesiocrinus 

 is there any suggestion of the rotund crown of the Lecanocrinidae, and none 

 of the genera have the closely abutting or interlocking rays and arms which are 

 found to a considerable extent in both the other families of this suborder. Anal 

 structures in some form exist throughout, including radianal of the primitive 

 and oblique types. Meristocrinus is aberrant in its characters, tending toward 

 the Taxocrinidae in its anal structure. 



Four of the five genera are Silurian, and while represented as late as the 

 middle of the Lower Carboniferous by the vigorous and widely distributed 

 Forbesiocrinus, the line of succession of this family through the Devonian is yet 

 to be discovered. One genus, Temnocrinus, is restricted to England, Litho- 

 crinus to Gotland, Meristocrinus to these two areas; while the other two, 

 Sagenocrinus and Forbesiocrinus, are common to both Europe and America. 



The name Sagenocrinidae was first used by Roemer in Bronn's Lethaea 

 Geognostica, 1852-54, p. 228, to include a single genus, Sagenocrinus, without 

 any hint of relationship to a larger group; and the genus was not at first in- 

 cluded in the present group by Wachsmuth and Springer. 



