68 Silurian Fossils of Canada, 



but differs by having the glabella parallel-sided instead of broad- 

 est in front, the terminal points of the tail obtusely instead of 

 sharply pointed, and the eyes further forward, being opposite the 

 second instead of the third pair of glabellar lobes. 



The largest specimen I have seen is about eleven lines in length. 



Locality and Formation. — Anticosti, Iludson River group. 



Collector. — J. Richardson. 



Proetus Alaricus. N. s. 



Fig. 12. — Froetus Alaricus, enlarged 2\ diameters. 



Description. — Oval, proportional lengths of head, thorax, and 

 pygidium about as 2, 2, 1. 



Head excluding the spines semicircular with a broad shallow 

 marginal groove all round ; spines extending backwards to the 

 sixth pleura. Glabella obtusely conical, about three fourths 

 the leno-th of the head, width at neck seofment four fifths the 

 length (of the glabella), sides parallel or very slightly inclining 

 towards each other for five sixths of the length, then curving 

 round to form the obtusely rounded front, neck furrow deep and 

 narrow. Eyes large, obtusely conical, half the length of the gla- 

 bella, their posterior angles on a line with the neck farrow, a little 

 more than their own length from the front margin, their bases 

 on the inside only separated from the glabella by an angular 

 furrow. 



Thorax with the axis prominent, semicylindrical, gradually 

 tapering backwards, about one third the whole width of the 

 body. There appear to be ten segments in the thorax. 



Pygidium semicircular with a prominent conical axis, which is 

 well defined at its posterior extremity and exhibits five or six seg- 

 ments. The side lobes of the pygidium appear to have five or 

 six ribs. 



The only specimen I have seen is five lines in leng^i but perfect. 



About the size and shape of P* latifrons (McCoy), but in that 



