266 John Rofe — Notes on the Crinoidea. 



the recent Pentacrinus at Figs. 1 and 6, in the illustration to my 

 paper as above, but which are not seen in the Chert specimen from 

 the Mountain Limestone, as the fibres passed through the central 

 screw-like portion, and not in bundles. In the Liassic Pentacrinites 

 the fibro-cartilaginous lobes are disposed very similarly to those in 

 the recent species, having a ring of pores round the central canal, 

 and five lobes radiating from it, as in Fig. 7, whilst in the elliptical 

 column of the Mountain Limestone Platycrinus (Fig. 8), and in the 

 circular column of the Oolitic Apiocrinus (Fig. 9), the pores are dis- 

 tributed round the centre canal. I have also some portions of 

 sub-pentagonal columns from Clithero, differing from those of other 

 genera found in the Mountain Limestone in that district, which are 

 generally circular in section. These vary in diameter from half an 

 inch to more than an inch ; a section of one is shown in Fig. 10. A 

 thin section under the microscope shows the fibro-cartilaginous 

 structure round the inner edge of the outer ring of the column, but 

 in no instance have I found the central portion so perfect as to show 

 the central canal or any organization. No head has been found 

 which can be supposed to belong to these columns, a remark which 

 applies to many other columns, and most particularly to the larger 

 ones, frequently found abundantly in the Limestone. Probably this 

 may be accounted for by the decomposition of the investing mem- 

 brane above alluded to. 



By the kindness of Mr. E. HoUier, I have procured pieces of 

 columns from the Silurian formation at Dudley, including Taxocrinus, 

 Periechocrinus, Actinocrinus, Marsupiocrinus, Cyathocrinus, and two 

 columns undetermined, as they were without heads. Of these I 

 have had slices mounted for the microscope, and find on examination 

 that, although there appears to be a general similarity in construction 

 with the round columns of the Mountain Limestone, as they are 

 more metamorphosed by crystallization, the details are more difficult 

 to distinguish. Some of them exhibit pentaphylloid sections of the 

 central canal, as the Taxocrinus and Cyathocrinus, whilst the Mar- 

 supiocrinus shows a rosaceous section, the petals being wide and the 

 divisions between them forming very acute angles; but I cannot 

 satisfactorily make out the fibro-cartilaginous structure round the 

 canal, though, from appearances, it is probable that it would be found 

 by further examination with a great number of specimens. 



JVbte on JEuryocrinus (Phillips). 

 This Crinoid, which, from its rarity and the very imperfect state of 

 the specimens hitherto found, is little known (neither the column, 

 arms, nor dome having been recognized), is yet interesting from the 

 peculiarity of the junction of some of the plates which form the cup. 

 The only published notice of this genus which I have been able to 

 find is in Phillips' Geology of Yorkshire, part ii. p. 205, and figured 

 in plate 4, figs. 14 and 15, which appear to be drawn from two speci- 

 mens in the Gilbertson collection now in the British Museum ; the 

 description given being merely, '' Pelvic opening pentagonal ; ar- 

 rangement of plates like Encrinus, internal cavity very large." A 



