498 Systematic Paleoxtology 



defined than the intercalated one, slightly sinuous, and terminating in a 

 deep cavity at cacli extremity : occipital annulation broad and strong, 

 slightly sinuate at the extremities, and, when entire, marked by one larger 

 central pustule and several smaller ones. 



Eyes of medium size, their summit less elevated than the glabella, ex- 

 tending backwards to the line of the occipital furrow, composed of seven- 

 teen vertical ranges of lenses; the entire number of lenses in full-grown 

 specimens about one hundred, and varying in the specimens examined 

 from ninety- three to one hundred and three. 



" The axis of the thorax is prominent, and narrower than each of the 

 lateral lobes; the annulations furnished with a prominent node at each 

 extremity. The lateral lobes are flat or somewhat concave towards the 

 axis, the articulations bending abruptly downwards from the middle 

 towards the extremities : each articulation strongly grooved, the groove 

 extending beyond the curvature. Pygidium semicircular; the axis promi- 

 nent, with about nine annulations; the lateral lobes having about five or 

 six ribs, each with a groove along the center. Surface of the glabella 

 pustulose, and of the articulations granulose, with some larger granules or 

 pustules. The crust is thin, and the interior of the glabella shows distinct 

 cavities corresponding to the external pustules. Hypostoma hastate; the 

 buccal extremity obtuse, with a minute central point." Hall, 1859. 



Occurrence. — Heldeeberg Formation, 'New Scotland Member. 

 Devil's Backbone, Corriganville, Maryland ; Cedar Cliff, West Virginia. 



Collections. — Maryland Geological Survey, "U. S. National Museum. 



[Ohern.] 



Phacops sp. ? 



Plate XCI, Figs. 5-7 



Description. — Two pygidia and a larger cephalon from the Oriskany 



are too poorly preserved to determine or describe. They are associated 



in the brown sandstone south of Cumberland and are assumed as belonging 



to the same species. 



Occurrence. — Oriskany Formation, Eidgely Member. Cumberland. 

 Collection. — George M. Boeder. 



[Ohern.] 



