306 Point Levi Fossils. 



side situated on a line drawn across the head passing through the 

 posterior half of the eyes ; in front of these a much smaller inden- 

 tation on each side representing the anterior furrows. The eyes 

 are small and conical, situated on a line crossing the glabella at 

 one half the whole length of the head, their distance from the 

 glabella equal to one-third the width of the neck segment ; ocular 

 ridge extending from the eye forward to a point situated a little 

 in advance of the anterior lateral indentation or furrow of the . 

 glabella. From the eye a strong ridge runs outwards to the 

 margin of the head in two of the specimens, but in another it is 

 not seen. Between the eye and the posterior margin and situated 

 near the posterior lobe, on each side is a large sub-semicircular 

 tubercle. This elevation is very slight in the small specimens. 

 The surface of the glabella and cheeks adjacent thereto are appar- 

 ently smooth but the whole of the concave border around the 

 head is ornamented with fine rugose striae distinctly visible to the 

 naked eye. 



Length of head in largest specimen seen eight lines ; length of 

 glabella six lines ; width of head fifteen lines; width of glabella 

 four lines ; distance between the eyes six lines. 



Thorax and pygidium unknown. I have not ascertained whe- 

 ther the posterior angles of the head are rounded or produced 

 into spines. 



Limestone No. 1. 



Genus Dikelocephalus. Owen. 



In the species which I have referred to this genus, the general 

 form and aspect of the glabella and pygidium and the course of 

 the facial suture are the same as in D. Minnesotensis the type of 

 the genus specimens of which I have before me from the sandstone 

 of the Western States. From numerous fragments of D. Oweni 

 exhibiting the underside of the head, I have ascertained that the 

 facial suture does not separate the cheeks from each other by cut- 

 ing the fold of the margin. The head is therefore composed of 

 three pieces only, — the glabella, hypostoma and united cheeks. 

 This separates the gtnus from Proetus, some species of which, such 

 as P. striatus (Barrande) have an expanded front margin and a 

 spinose pygidium very like those of D. magnijicus. The head of 

 Proetus consists of five pieces. The hypostoma found associated 

 with our specimens is much like that of Proetus^ and it is also 

 not unlike that of Ogygia. According to the figure given in 



