1^ 



212 PALAEONTOLOGY. 



tlie thorax ; segments distinct, moderately elevated, slightly flattened, and, 

 on the older specimens, having obscure flattened tubercles at the outer 

 extremities ; lateral lobes convex, flattened on the inner half, and gradually 

 rounding on the outer portion, becoming flattened and slightly concave 

 Loward the free ends of the pleura. Pleura straight for nearly one-half 

 iheir length, beyond which they are directed backward with an increasing 

 curvature to the free ends ; fun-ows broad and deep, occupying nearly the 

 entire breadth of the pleura on the sti-aight portion, beyond which they are 

 narrowed, and become obsolete on the flattened part of the extremities. 



Pygidium small, elliptical, the anterior and posterior margins nearly 

 equally rounded ; outer angles obtuse ; surface convex, strongly trilobed ; 

 axis not quite one-third of the entire width, prominently convex, and reach- 

 uig nearly to the posterior margin, marked by three rings exclusive of the 

 terminal ones ; lateral lobes depressed-convex, marked by tliree pairs of 



« 



furrows, which are curved backward, and become obsolete before reaching 

 the margin. 



This species difiers from ConocepliaUtes {Conocoryphe) Kingii Meek in 

 its broader form, proportionally wider axis, and smaller pygidium ; in hav- 

 ing one less thoracic ring, a broader and less conical glabella; and in the 

 broader furrows of the pleura, as well as in several points of minor import- 

 ance. It also bears considerable resemblance to Loganellus Logani Devine 

 (Pal. Foss. Canada, vol. 1, pp. 200 and 201), but diifers conspicuously in the 

 proportionally larger cephalic shield, larger cheek-spines, and in wanting 

 the extended extremities of the pleura, as in that species. 



Formation and locality. — ^In dark-colored limestone of the Potsdam 

 group, on the west side of Pogonip Mountain, and near French Mine, 

 White Pine District, Nevada. Collected by Arnold Hague, esq. 



GrEEICEPH ALUS (Log ANELrLUS-) KITIDUS 1). Sp. 

 Plate II, fiRS. 8-10. 



Glabella pyramidal, squarely truncate in front; lateral margins nearly 

 straight; height above the occipital furrow less than the width at the base, 

 and the anterior end equal in width to the entire height, including the 

 occipital ring, separated from the fixed cheeks by well-defined, rather deep, 



