492 GEOLOGY AND MINERALOGY. 



eye to the frontal margin, less than the length of the eye. Glabella lobed ; hy- 

 postoma broad oval. 



Thorax imperfect, preserving six articulations and part of the seventh ; the 

 middle lobe wider than the lateral ones. The third articulation is much broader, 

 towards and at its lateral margin, and is prolonged obliquely downwards in a 

 sharp spine, which reaches below the seventh articulation ; the lateral extremities 

 of the other articulations produced in short acute spines. 



Another fragment, which is apparently of the same species, preserves eleven 

 articulations of the thorax and the pygidium. The upper articulations are imper- 

 fect at their extremities ; the last one is bent abruptly downwards, and terminates 

 in a long spine on each side, reaching below the pygidium. Pygidium semioval ; 

 the axis marked by four annuiations, the two upper of which are faintly indicated 

 in the lateral lobes. 



This species differs from the preceding, in its proportionally narrow form, the 

 relative proportions of the parts of the head, and the short acute posterior spines. 

 The comparative width of the middle and lateral lobes of the thorax is a very 

 distinguishing feature. 



Geological position, — In the shales of the upper pact of the Hudson River group. 



Feltura {Olenus) Ilolopyga. (n. s.) 



Entire form elongate subelliptical, having a length of about twice and a half the 

 width. Head somewhat eemielliptical ; the posterior angles produced in long 

 spines. Glabella strongly lobed, its length a little greater than its greatest 

 breadth ; the entire breadth of the head, when entire, being about twice as great 

 as the length. Hypostoma wider than long. 



Thorax with eleven articulations ; the middle lobe prominent, and about twice 

 as wide as the lateral lobes ; the articulations strong, rounded above, and each one 

 marked in the centre by a node (or the base of a spine which has been broken off 

 in the specimens examined). Articulations of the lateral lobes short (the extremi- 

 ties of the upper ones broken off in the specimen) ; the lower ones bending abruptly 

 downwards, and terminating in spiniform processes, the last pair being prolonged 

 much beyond the extremity of the pygidium. 



Pygidium longitudinally semielliptical ; the middle lobe marked by three annu- 

 iations, and a fourth obscure one above the terminal lobe ; lateral lobes flat and 

 plain, the exterior margin apparently free from ornament or inequality. 



This species appears to belong to the genus Feltura, taking the figures of Olenus 

 (Pelticra) scarahceoides as the type of the genus.* Our specimen differs from that 

 one in the absence of the obscure crenulations or inequalities upon the limb of the 

 pygidium, which is regarded by Pictet as important. The number of segments of 



* This species, the JEntamostraticites scarahceoides of Wahlenberg, 1821 {scarabceonmi 

 vel aliorum vaginipennium animate vestigia : Bromel in Act. Litt. Upsal. 1729,) has appa- 

 rently been reflgured from the same specimen, or from the same figure throughout, by sub- 

 sequent authors ; and the original appears to have been deprived of the cheeks, the frontal 

 limb, and the posterior cephalic spines. The eye-tubercle, or the palpebral lobe, having col- 

 lapsed as in our specimen, gives but a partial representation of the entire animal. 



