d98 PALEONTOLOGY OF NEW-YORK. 



Pdtum (Oleiius) iiolopyt^a (n.s.). 



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

 half the width. Head somewhat semielliptical ; the posterior angles 

 produced in long spines. Glabella strongly lobed, its length a little 

 greater than its greatest breadth ; the whole 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 ). Arti- 

 culations of the lateral lobes short (the extremities of the upper ones 

 broken off in the specimen) ; the lower ones bending abruptly down- 

 wards and terminating in spiniform processes, the last pair being 

 prolonged much beyond the extremity of the pygidium. 



Pygidicm longitudinally semielliptical ; the middle lobe marked by three 

 annulations, and a fourth obscure one above the terminal lobe : lateral 

 lobes flat and plain, the exterior margin apparently free from ornament 

 or inequality. 



The specimen from which the description and figure have been made is imperfect, 

 in the absence of the cheeks with the posterior spines and fronfcil limb. Tliese parts, 

 with the hypostoma attached, lie upon the stone a little in advance and turned to 

 one side of the head of the specimen, and have been drawn in their proper relations, 

 but not attached to the head. That this portion of a trilobite belongs to the one 

 figured, can scarcely admit of doubt; but in the absence of an entire head, which 

 would warrant the restoration, I have given the figure as it occurs on the stone, 

 with merely a change of the position of the two parts. It is not proved, from this 

 specimen, that the third articulation from the head may not have extended beyond 

 the others, as shown in the two preceding species. 



This species appears to belong to the Genus Peltuha, taking the figures of Olenus 

 (Peltura) scarahaoides as the type of the genus*. Our specimen diflFers from that one 



* ThU npccics, the Entomottracitet tcarabaoidet of Wahlenbero, 1821 ( icarabeeorum vel aliorum 

 vaginipennium animale vettigia .- Bbomei. in Act. Litt. Upsal. 1720), has apparently been drawn iVom 



