244 PALEONTOLOGY. 



The pygidium is associated Avith a graiiulose glabella of corresponding 

 dimensions, wliicli is too imperfect for illustration or description, but prob- 

 ably of the same species. The sides are parallel or slightly widening ante- 

 riorly, and the front rounded. The entire surface is covered with small, 

 closely-set pustules. The glabella bears considerable resemblance to that 

 of B. strenmis Bill. (Pal. Foss. Canada, vol. 1, p. 204), but shows indica- 

 tions of a faint glabellar furrow behind the middle of the length. 



Formation and locality. — In coarse, crystalline limestones, on the west 

 side of Pogonip Mountain, White Pine, Nevada. Collected by A. J. 

 Brown, esq. 



Genus OGYGIA Brongn. 



Ogygia. producta n. sp. 



Phitell, figs. 31-34. 



Glabella very much elongated, twice as long as wide, measuring from 

 the occipital furrow; slightly expanded in front, and rounded on the ante- 

 rior extremity; convex and subangnlar along the median line; marked by 

 two pairs of faint, very oblique furrows, which do not quite meet in the 

 middle. Occipital furrow broad and distinct; ring strongly marked and 

 thickened in the middle. 



Fixed cheeks of moderate width; eye-lobes large, two-thirds as long 

 as the glabella, extending from the occipital furrow to the middle of the 

 anterior lobe of the glabella; distinctly marked by a narrow, depressed 

 furrow just within and parallel to their margins. Lateral limbs narrow. 

 Frontal limb imknown. 



Movable cheeks obliquel}' triangular, the outer face being miich the 

 longest, and regularly arcuate; posterior extremity rounded, showing no 

 evidence of a spine in the impression of the under surface, though the 

 vxpper portion may have borne a spine, as seems to be indicated by other 

 impressions of the exterior. Ocular sinus very large, but shallow, regu- 

 larly arcuate; surface of the cheek depressed-convex, with a faiiit, shallow 

 groove just within the margin and a scarcely thickened rim beyond. 



Thorax depressed-convex, distinctly trilobed. Axis narrower than the 

 lateral lobes, and gradually tapering from the occipital region posteriorly, and 



