258 DESCRIPTION OF THE SPECIES OF PTERYGOTUS 
and altered in shape than the other, 4. The dotted lines will give a 
notion of what was probably the complete form. Fig. 9 is probably 
a similar fragment. Figs. 10 and 11 have as yet no explanation. 
Fig. 7 shows the true outline of another ring, which has been com- 
pressed vertically in the rock, instead of laterally. These specimens 
of course give the true idea of the convexity, which was very great. 
The form was almost cylindrical. 
Of the intermediate rings we have very few fragments, but 
several hinder rings, which must have been near to the extremity 
both from their form and their being quite covered with the elongate 
tubercular plice. 
Plate IX. [Plate 20] fig. 7, from the cabinet of Mr. Marston, 
represents probably the penultimate ring. It is two inches and a 
quarter long by two inches at its truncated extremity, which is 
rather wider than its base. The shape is thus nearly square, the 
Fic. 14. 
Anterior body rings of Prerygotus punctatus. The first segment lost. From Lower Ludlow 
Rock, Leintwardine. In the collection of Mr. J. Harley, 
sides are but very slightly (perhaps not at all) curved, nor is the 
base a contracted or the distal end 6 expanded or produced, as in 
P. anglicus. The edge is crenate. Plate XIII. [Plate 24] fig. 5 is 
from the Upper Ludlow Rock. 
The caudal joint (telson) is yet wanting and should be sought 
for, as in all probability it was not unlike that figured on Plate VIII. 
[Plate 19], fig. 11 has possibly something to do with it. 
Mr. J. Harley, of King’s College, has found a small specimen, 
doubtless of this species (woodcut, fig. 14), since the plate was 
finished. It has the second to the sixth rings united, and the 
pyramidal form of the front ring is very marked. 
