Point Levi Fossils. ,203 



one-third, or a little more, of the length from the front. The 

 posterior furrow is interrupted in the middle and is only distinct- 

 ly seen on each side, penetrating one-third the width, while its po- 

 sition is a little in advance of the posterior third of the length of 

 the glabella. The space between the two inner extremities of the 

 posterior furrows is occupied by a low conical tubercle, with the 

 apex directed backwards. At each side of the glabella at the 

 posterior extremity there is a small triangular lobe. The glabella 

 is defined all round by a very narrow groove, just distinctly visi- 

 ble to the naked eye, and from the apex a similar groove runs 

 straiirht to the middle of the front majojin. The surface is orna- 

 mented by from fifteen to twenty irregular, slightly impressed, 

 radiating rugose striae. 



Fig. 1. Fig. 2. Fig. 3. 



Fig. 1. — Jgnostus Americanus ; a, the tail ; 6, the head ? Both a little 

 magnified. 



Fig. 2. — jlgnostus Orion. Natural size. 



Fig. 3. — jlgnostus Canadensis ; «, the tail ; h, the head ? Both mag- 

 nified. 



Note. — All the figures in this article are of the natural size^ unless 

 otherwise specified. 



In the pygidium the posterior segment of the median lobe is 

 equal to the two anterior in size ; and there are no triangular 

 lobes at the anterior margin. The tubercle is well developed, 

 and its backward sloping apex reaches nearly to the posterior 

 furrow. It seems to divide the two anterior seofments so that each 

 has a sub-quadrate lobe on each side. The surface is striated like 

 the head. Two heads and one tail have been found. 



Length of the tail three lines and one-fourth ; of the largest 

 head, three lines, and of the other two lines and three-fourths. 

 The width is about equal to, or a little less than the length. 



The contour appears to be not a regular semi-oval ; the sides and 

 terminal margins being only gently convex, and the angles broadly 

 rounded. 



