34 
BULLETIN OF THE NATURAL HISTORY SOCIETY. 
ARTICLE III. 
PROTOLENUS — A NEW GENUS OF CAMBRIAN TRILOBITES. 
BY G. F. MATTHEW, M.A., F.R.S.C. 
Fragments of a trilobite which appeared to be an Olenellus 
had in past years been found in the beds of Band b., Division 
1, of the St. John group, at Hanford Brook, St. Martin’s, and 
in the summer of this year, 1892, 1 sent my son, W. D. Matthew 
there, to search for better examples. Though unsuccessful in 
this quest, he found remains of other forms of trilobites in 
these lower beds of the Cambrian, which serve to extend our 
view of the range and variety of the early Cambrian genera. 
Among these remains were the head-shields and body-joints of 
the genus herein described. 
Protolenus.* n. gen. 
Head-shield semicircular, moderately vaulted, outer part of 
the cheek movable, prolonged at the genal angle into a spine. 
Middle piece of the head more or less quadrate. Anterior 
margin wide and having a narrow distinct fold at the rim. 
Glabella conical or cylindro-conical, prominent, marked by 
furrows on the sides, and distinct from the occipital ring. 
Fixed cheeks of variable width, bordered by a long, continuous 
or nearly continuous eyelobe. Extension of the dorsal suture 
both in front of and behind the eye, more or less direct to the 
margin. 
Movable cheek regularly curved, area wider than the dis- 
tinct fold, spine usually long. 
Thorax of many joints, pleuras grooved for part of their 
length, slightly geniculate, curved backward in the distal 
part, extended into points or spines. 
Pygidium in the Canadian species unknown (small ?) ; in 
the Sardinian species like that of Paradoxides (or of Olenus.) 
*Protos , first, olenus , as one of the Olenidai, 
