338 SMITHSONIAN INSTITUTION 



of basals and meeting them by their inner edges ; while in figure 9 they have completely dis- 

 appeared, not by being pulled off with the stem as in Forbesiocrinus, but by atrophy as a 

 morphological feature in that specimen — just as they do in the Recent species Endoxocrinus 

 parrae — and the space they should have occupied is partly represented by the large lumen of 

 the axial canal. 



A curious degenerate tendency appears in the anal interradius, where the lower plate is 

 wanting in most of the specimens. 



In the basal structures and general habitus the genus is similar to Euryocrinus, but 

 differs from it in the relative development of the anal side, and in having only two primibrachs 

 instead of three. On the latter character alone it might be held to be a variant, as in the case 

 of Forbesiocrinus agassizi; but the interbrachial structure strongly differentiates it, and this 

 correlation of characters is the fundamental ground for the generic separation which I made. 



The type species is from the Hurlet limestone of the Lower Carboniferous of Scotland, 

 a different and much later horizon than that of Euryocrinus concavus and E. rofei, and sub- 

 stantially equivalent to the American Kaskaskia. Until recently but few specimens have been 

 found, and it is rather curious that this hitherto unnoticed fossil should be one of those most 

 prominently figured by David Ure in 1793. A second species has been discovered in the 

 Lower Coal Measures (Pennsylvanian) of America, which makes this genus the latest known 

 survivor of the Flexibilia. 



Amphicrinus scoticus n. sp. 



Plate XL, figs, p-11 



Amphicrinus scoticus Springer MS., Wright, Trans. Edinburgh Geol. Soc, X, pt. 2, 1914, p. 161, pi. 19, 



figs. 3, 4. 

 Encrinus, Ure, History of Rutherglen, 1793, p. 325, pi. 18, figs. 13, 16. 

 Forbesiocrinus spp. Wright, Trans. Edinburgh Geol. Soc, X, pt. 1, 1912, pp. 49-60, pi. 5, fig. 8, pi. 6, 



figs. 1, 2, pi. 7, fig. 1. 

 ? Euryocrinus sp. Wright, Trans. Edinburgh Geol. Soc, X, pt. 1, 1912, pi. 7, fig. 3. 



Type of the genus. 



Specimens above medium size. Crown rotund, higher than wide; with 

 small base, and closely abutting, infolding rays. Surface smooth. Greatest 

 width of average specimen at IIIBr 3 , about 35 mm. ; height 40 mm. ; spread of 

 calyx from base to top of iBr, about 1 to 3.5. 



Base very shallow, and broadly expanding to above the second ray division. 

 IBB very small, lying entirely within BB, sometimes partly or wholly resorbed. 

 Post. B more than twice as large as the others, and rising far above their level; 

 the other four small, usually covered by the column, exceptionally visible as 

 small triangles outside the column facet. RR small, only partly visible beyond 

 the column, the two posterior ones smaller than the others. IBr 2, larger than 

 RR, somewhat widening upward ; the next two orders of brachials fully as large. 

 IIBr 3, increasing in width upwards; IIIBr 5 or 6. Arms flat, and following 

 the general curvature; interlocking" closely above iBr and illBr by zig-zag lines, 

 and infolding at about the fifth order of brachials. Sutures arcuate, more 

 strongly marked in distal parts of rays. Post. B truncate, followed by a single 

 diminishing series of plates smaller than one of the two columns of inter- 



