ICHTHYOCRINIDAE 34I 



Amphicrinus carbonarius n. sp. 



Plate LX, figs. 12a, b 



I have figured under this name an imperfect specimen, which is of special interest as 

 being the latest known survivor of the Flexibilia as now limited by me to the Impinnata. It is 

 derived from the Lower Coal Measures (Pennsy'lvanian) at Girard, Kansas, and has been 

 lying in my collection for many years without a name, because the parts preserved are not 

 sufficient to determine its generic characters. It is of an extremely flexible type, having broad 

 and shallow ligament fossae somewhat like those of Forbesiocrinus, which it also resembles 

 in the relative thinness of the lower plates. The only previously described genera approxi- 

 mating its geological position -to which it might possibly belong are Forbesiocrinus and 

 Parichthyocrinus, and I arranged it on the plate with the latter purely on the ground of 

 superficial resemblance, as the lack of knowledge of the anal structures precluded any deci- 

 sive comparison. Both of these genera, so far as known, ended with the Keokuk, and from 

 there to the Coal Measures seemed a long leap without any vestige of these forms among 

 the abundant collections from the intervening Kaskaskia. The subsequent discovery of 

 Amphicrinus from the British rocks, in a horizon substantially equivalent to the Kaskaskia, 

 suggested a new possibility, and the study of Mr. Wright's series of specimens leaves no 

 doubt that the Kansas fossil belongs to the same genus. This determination fits the case 

 beautifully upon stratigraphic grounds, as the Hurlet limestone shades into the Coal Meas- 

 ures ; and it is to be hoped that some of our collectors in the Pennsylvanian area may find a 

 complete specimen by which it may be confirmed. 



Of specific characters not much can be said, the narrow and rather angular distal arm 

 branches of the present form being the only one noticeable. The specimen occurred in a 

 thin layer of shale, where it was vertically crushed to a flattened mass, of which the dis- 

 integrated remnants of the calyx minus the base and primibrachs constitute one side, and the 

 infolded arms, fairly intact, the other. From what is preserved of the distal portion of the 

 rays (PI. LX, fig. 12b), the arms appear to be rather short, tapering to thin, sharp-backed 

 finials ; they are closely abutting, with a somewhat unequal branching toward the end. The 

 lowest bifurcation seen in this view is evidently the third, so that the scattered calyx-plates 

 lying upon the opposite side (fig. 12a) are probably chiefly secundibrachs. The lateral faces 

 of these show very plainly the strong ligament fossae for attachment of interbrachials, and 

 several such plates can be recognized. These are all below the level of the tertibrachs, and 

 it is clearly evident that the rays, and perhaps in part their first divisions, abutted closely 

 above them. The sutures in the visible parts of the rays are strongly arcuate. 



Type. In the author's collection. 



Horizon and locality. Lower Coal Measures, Pennsylvanian ; Girard, Kansas. 



