POTERIOCRINUS. 227 



approach P. crassus, and is therefore probably a typical Poteriocrinus. That 

 specimen is accompanied by three gutta-percha casts, which appear to have 

 brought away portions of the cup as they were taken, so as to enable the plates 

 to be counted, though in one their interior, and in the others their exterior, casts 

 are seen. Part of its ventral sac is exposed. Two bifurcations may be traced in 

 the arms, but whether the plates below the first of these are primibrachs or 

 secundibrachs is not clear; the arms seem hardly sufficiently numerous for the 

 latter. No pinnules are visible. 



In Miss Partridge's fine fossil, on the other hand, no bifurcation of the arms 

 is observable, and this must throw some doubt on its identity with the other 

 specimen. The arms appear ten in number (eight are seen), and they bear 

 remarkably long and slight distant pinnules, having ten or twelve distant joints. 



2. POTERIOCRINUS BARUMENSIS, Whidborne, sp. Plate XXXIV, fig. 6 ; and Plate 



XXXV, fig. 3. 



1896. CTATHOCEINUS BAEUMENSIS, Whidborne. Proc. Geol. Assoc., vol. xiv, 



p. 377. 



Description. Rather small. Stem cylindrical ?, composed of short alternating 

 coliunnars. Cup short, obconical. Infra-basals five, pentagonal, as high as wide. 

 Basals small, hexagonal, as high as wide. Radials five, large, pentagonal, truncated 

 above, as high as wide. Primibrachs five, large, pentagonal, as long or longer 

 than the radials, axillary. Arms stout, very long, uniserial with truncated cuneate 

 plates, and bearing very long close pinnules. Anal side unknown. Ventral sac 

 large, long, composed of slightly transverse pieces with stellate marks. 



Size. A cup measures 7 mm. wide and 6 mm. high. 



Localities. There are two specimens (from Top Orchard Quarry and from 

 Barnstaple) in the Woodwardian Museum. An indistinct specimen from Fre- 

 mington is in the Porter Collection, and its reverse in Miss Partridge's Collection. 



Remarks. At first I supposed these fossils to be specimens of P. tensus, but 

 further examination convinces me that they cannot be included in that species. 

 The cup is much shorter and more globose, the basals smaller and primibrachs 

 larger and single, and the columnars circular. 



The stem in one of the specimens (PI. XXXV, fig. 3) shows a curious 

 deformity. Across one (and perhaps a second) longitudinal line the columnars 

 are not continuous, but meet alternately, their line of junction being marked by a 

 zigzag suture. 



GG 



