ORDER III CRINOIDEA—FISTULATA 157 
Mastigocrinus, Bather. Probably merely a variety of Cyathocrinus, with 
which it agrees in structure of the calyx and mode of branching. The arms, 
however, are relatively longer, as is also the ventral tube ; column quinque- 
partite. Silurian; Dudley, England. 
Botryocrinus, Ang. Calyx small, cup-shaped, unsymmetrical. J five, high, 
slightly protuberant. J five, three of them hexagonal and equal ; the posterior 
pair indented by the radianal. J five, very large, with excavated facets. LA 
small, rhomboidal, and supporting the ventral sac. Arms ten, giving off 
armlets from alternate sides of each or of every second or third joint 
throughout their entire length; in some species the armlets give off sub- 
branches. Ventral sac in the form of a tube which coils upon itself like a 
snail at about one-fourth the height of the arms. Anal opening situated 
anteriorly at the base of the tube. Silurian; Gottland. 
Barycrinus, Wachsm. Differs from Cyathocrinus in haying massive arms, 

Fic. 262. 
MIG. 261. ve = ae m F . 
Fic. 261 a, Gissocrinus arthriticus, Phill. Silurian; Gott- 
Lecythocrinus Pifelianus, land. Crown of the natural size (after Angelin) ; 
Mill. Devonian; Eifel. Re- b, G. punctuosus, Ang. Tegmen; c, Ventral and 
stored (after Schultze). lateral aspect of the arms (enlarged). 
composed of rather short, heavy, almost circular pieces, and exhibiting very 
narrow ambulacral furrows. In some species the /?A sustains a diminutive 
supplementary piece to the right, which is wanting in others. Ventral sae 
composed of but few rows of heavy plates, longitudinally arranged. Column 
stout, obtusely pentagonal, and quinquepartite ; axial canal very large. Sub- 
Carboniferous ; North America. 
Euspirocrinus, Ang. (Fig. 219). Dorsal cup conical, composed of massive 
plates. JB five; B five; A with a deep and broad articular facet, notched for 
the passage of the axial cord. JRA large, rising above the level of the R. 
Radianal somewhat smaller, and supporting a plate of the ventral: tube 
which takes part in the dorsal cup. ‘Tube cylindrical, composed of relatively 
large plates. Tegmen formed of five interradial pieces, which support by their 
lateral edges two rows of side pieces enclosing an irregular row of covering 
plates. Madreporite small; column quinquepartite. Silurian; Gottland. 
. 
