BRITISH FOSSILS. 



PLATE XIV. FIGS. 1 TO 13 ; PLATE IX. FIG. 18 ?; 

 PLATE XII. FIGS. 1 TO 5 (AND 6 ?). 



P. LUDENSIS. 



P. major, segmentis carports omnibus transversis, decimo bis quam longer 

 latiore, penultimo subquadrato vix expanso, supra carina percurrenti; 

 cauda ovali breviapiculata obtusicarinata : super/icie toto pi ids curvatis 

 simplicibus ornato. 



Under this name I would now describe, witli but little doubt of 

 its specific distinction, the fragments of a fine species very abundant 

 indeed in the transition beds of Ludlow, shown as they are in the 

 railway cutting near that town. All the specimens are in the 

 cabinets of Mr. Lightbody and his son. The same species is found 

 at Trimpley near Kidderminster, and we are indebted to Mr. G. E 

 Roberts for the means of illustrating some points not clear in the 

 specimens at Ludlow. 



The materials consist of several body rings of large size, Plate 

 XIV. fig. 2, 3, 4, 11 ; a fragment of the caudal joint, fig. 12; the 

 epistoma ; a specimen, fig. 1, showing nearly all the body joints and 

 telson in position, but a good deal obliterated ; the serrate bases of 

 the swimming feet, figs. 8, 9 ; mandibles with palpi, figs. 5, 6, 7 ; 

 antennae, fig. 10 ; and to these must be added certain figures in 

 Plate XII., showing the antennae, figs. 1, 2 ; the post-oral plate, 

 fig. 3 ; the bilobed (abdominal ?) appendages, figs. 4, 5 ; and possibly 

 the portion of the swimming foot, fig. 6 ; together with the imper- 

 fect caudal joint in Plate IX. fig. 18. The two last may, however 

 belong to P. gigas, a species very nearly allied, and to which for 

 some time I believed the whole of the specimens referable. Again, 

 there is so much resemblance in certain points to the Scotch species, 

 P. anglicus, that it requires nice discrimination to separate the three 

 forms. The characters of the antennae, and also of the caudal 

 joint, will, I think, be sufficient. And if subsequent observation 



