51 



great depth to the furrows which divide them from the glabella; 

 the lateral borders thickened with a rounded margin. On the 

 inside of the projecting border, in front of the glabella, there 

 are two large rounded tubercles, which form a conspicuous 

 feature. 



Pygidium semi-elliptical, the central lobe or axis not very 

 prominent, marked by seven annulations besides the terminal 

 one, which is nearly as long (wide) as the three preceding, 

 obtusely rounded posteriorly: the lateral lobes are broad, 

 nearly twice the width of the central lobe at its junction with 

 the last thoracic segment; marked by six broad flattened ribs, 

 which become obsolete before reaching the margin ; the ante- 

 rior five are divided in the middle or on the outer half of their 

 length, by a narrow sulcus. 



Surface of the whole crust of the body, so far as seen, 

 covered with fine rounded papilke. 



This species somewhat resembles C. diademata, Ban*., but 

 the glabella is much narrower in front, the two anterior pairs 

 of lobes in the sides are much smaller, the cheeks more prom- 

 inent, and the projection in front of the head much more 

 extended; also, the two rounded tubercles, characteristic of 

 this species, are not possessed by that one. The pygidium is 

 narrower, and has one annulation more than C. diadementa. 



Geological Formation and Locality. In the shales above the 

 Galena limestone, Makoqueta creek, twelve miles west of Du- 

 buque, Iowa. 



Colletor. T. J. Hale. 



GENUS DALMANITES, Emmerick. 

 DALMANITES vigila&s, (n. s.) 



JJcscription. General form of body not determined. Ce- 

 phalic shield convex, semi-elliptical, the breadth about twice as 

 great as the length, (exclusive of the frontal projection,) the 

 border extended in front into a triangular flattened process, 

 the base of which is little less than one-half as wide as the 

 width of the anterior portion of the glabella. In older indi- 

 viduals this projection becomes more obtuse and sometimes 

 rounded, the lateral borders are broad, flattened, separated, 

 from the cheeks by a distinct groove, extended posteriorly into 

 s.pines which are equal in length to the glabela. 



Glabella large depressed convex, widening in front to twice 

 the width of the posterior margin ; divided into lobes by three 

 pairs of transverse furrows exclusive of the occipital furrow, 

 which is distinct and continuous : the two posterior furrows 



