254 Cincinnati Society of Natural History. 



DESCBIPTlOir OF TWO NEW SPECIES FROM THE 



NIAGARA GROUP, AND FIVE FR03I THE 



KEOKUK GROUP. 



By S. A. Miller, Esq. 

 Encrinurus egani, n. sp. 



Plate XV., fig. 1, general view of a specimen, having one eye tubercle removed ; la, view 



of the head with the spines removed ; 16, view of the head from the rear, 



showing the spines. 



Corpus — The general form is somewhat elliptical, with the exception 

 of an angular pj^gidiuni. 



Caput — The cephalic shield has the form, in front, of one end of an 

 ellipse, and the posterior angles terminate in spines, which extend 

 backward about half the length of the thorax. The length from the 

 neck furrow to the front is less than half the width measured at the 

 same furrow. It is bordered by a rim which is very narrow in front, 

 but stronger posteriorly, and in its continuation forms the spines. 

 The rim is ornamented with a row of tubercles. The glabella is 

 clavate and gibbous, projects in front beyond the narrow rim, and 

 contracts between the e^^es to less than half its anterior width. It is 

 separated from the cheeks by remarkably deep furrows, and is cov- 

 ered by strong tubercles, which are arranged, in some specimens, in 

 seven to eight transverse rows. There are four tubercles in the 

 posterior row, and as the glabella expands in front, they increase to 

 more than twice this number. The cheeks are narrow, and slope 

 abruptly from the ej'es to the marginal furrows. The facial sutures 

 are directed from the e3^es forward, so as to reach the margin at the 

 anterior part of the glabella; and from the eyes outward curving 

 backward to the spines at the posterior angles of the cheeks. The 

 occipital furrow is continuous. 



The e^^es are very large, the bases projecting over part of the occip- 

 ital furrow, and the furrows separating them from the glabella, and oc- 

 cupying a considerable part of the cheek area. The eye bases are cov- 

 ered by large tubercles. The eyes are pedunculated, and project for- 

 ward and outward, like two little horns, until the ends are separated by 

 a distance equal to the diameter of the cephalic shield. 



TJiorax — The thorax has eleven segments. The axis is convex, 

 narrower than each of the lateial lobes, and marked 'by a row of tu- 

 bercles upon each side as in Calynieiie niagarensis. The lateral lobes 

 are flattened toward the axis, and l)end abruptly downward from the 

 middle toward the outer side. The articulations curve backward and 



