124 



Contributions to Palaeontology. 



Plate iv, Fig. 1, shows the form of the glabella and fixed cheeks. 

 Fig. 2. The pygidum. 

 Fig. 3. A movable cheek. 

 Fig. 4. The hypostoma. 



In the collection from Lagrange mountain in Minnesota, this 

 species greatly outnumbers its associate the D. minnesotensis. It is 

 not known to attain so large a size, nor does it occur in other locali- 

 ties so frequently, as that species. In the Mazomania collections I 

 have seen but a single individual, and I have no specimens from 

 any other place. Dr. Owen has cited only the locality of Lagrange 

 mountain for this species. 



DIKELOCEPHALUS SPINIGER ( n. s.). 

 PLATE V. FIGS. 1, 2 & 3? 



Glabella somewhat semicylindrical, very convex ; sides 

 gently converging, truncate in front ; length, little greater 

 than the width : posterior furrows very oblique «and 

 deeply impressed for nearly one-third the width of the 

 glabella, and continued by a more shallow furrow across 

 the summit ; second furrows indented at the sides, and 

 continued across the glabella in a scarcely perceptible 

 impression. The anterior furrows are slight indenta- 

 tions in the sides of the glabella, leaving a very narrow 

 anterior lobe. The occipital furrow is deeply impressed, 

 straight in the middle, and bending a little forward 

 towards the extremities : occipital ring convex above, a 

 little curving forward at the sides and very prominent 

 in the middle, supporting a spine. Dorsal furrows 

 strongly impressed, and more deeply marked in front of 

 the glabella. The frontal limb is a regularly convex 

 elevated band. 



Fixed cheeks narrow at the sides, expanding in the direc- 

 tion of the palpebral lobes, which are defined by a 

 strong furrow. The posterior limb is unknown. 



