KONINCK NEW PALAEOZOIC CRINOIDS. 181 



on the left of the anal plates is hexagonal, its general form also is not quite the 

 same as that of the other radial plates ; that on the right differs totally from these : 

 it is in some sort quadrangular, slightly transverse, and furnished on the left side 

 with a little prolongation corresponding to the second anal plate. The figure below 

 will display, better than any description could explain, the differences which 

 exist between the various pieces. 



The two first anal pieces only are known to me ; the one rather large pentagonal, 

 and a little longer than broad ; its upper side is narrow, and supports the second 

 plate, also pentagonal, but extremely small. The thickness of all these plates 

 being considerable, the free space occupied by the animal is thus very much 

 restricted, and the calix, as seen from the upper side, presents but a very narrow 

 opening, and is not unlike, especially in the articular surfaces of the radial plates, 

 the head of the Apiocrinus. PI. iv. f 4. & l^. The stem ought to be small and 

 cylindrical, judging from the small diameter and the form of the impression left 

 by its last articulation on the base of the calix. 



Dimensions. — Length of calix I3°i™, largest diameter 12ram^ diameter of 

 superior edge S^m^ ef the stem '1^^ ; length of sub-radial plates about 6mm, 



Affinities and Differences. — The Poteriocrinus nuciformis/-' AT'Coy, is 

 ' the only species of crinoid which approaches this, but differing in its 

 more elongated form, and still more in the welding of the two little 

 anal plates at the upper edge of the former, whilst our species has 

 but one in this situation. 



Position and Locality. — This species has been found with the pre- 

 ceding in the environs of Glasgow. I know only two specimens, deposited 

 in the Museum of the Geological Survey, at London; and it is also to the 

 kindness of Mr. Salter, that I am indebted for my acquaintance with 

 them. 



Explanation of figures. — PI. lY : — 



Fig. 1 . — Specimen, of natural size : the anal side. 

 Fig. la. — The same, twice magnified : the same view. 



Descript. Brit. Pal. Foss. Mus. Cambridge, p. 117, PI, 3D. fig. 4. 



