NO. 5 CAMBRIAN TRILOBITES 379 



ORRIA, new genus 



General form elliptical, moderately convex. Cephalon semicircular 

 with a border of medium width terminating at the genal angles in a 

 short spine ; the glabella widens very slightly towards the front and 

 is marked by a distinct pair of oblique posterior furrows that are 

 connected by a very shallow transverse furrow ; second pair of fur- 

 rows short and extending less obliquely backward onto the glabella ; 

 third pair short and nearly at right angles to the side of the glabella ; 

 fourth and anterior pair extending inward and a little forward ; * 

 occipital ring of medium width and marked on the posterior side by a 

 narrow band that is broadest at the center and sloping away at the 

 sides ; it has the appearance of a crowding forward of transverse 

 lines toward the base of the small tubercle ; a minute, sharp-pointed 

 tubercle occurs at the front center margin of this band which is also 

 marked by irregular raised lines subparallel to the front margin of 

 the band. A similar band and tubercle occurs on each of the thoracic 

 segments and the anchylosed segments of the pygidium. Fixed 

 cheeks little more than a line between the glabella and rather large 

 palpebral lobes ; they merge posteriorly into narrow lateral limbs that 

 extend out beyond the line of the termination of the thoracic seg- 

 ments ; each limb has a broad, shallow intramarginal furrow that 

 occupies nearly all of its surface ; anteriorly the fixed cheek is very 

 narrow and curves forward to merge into a very narrow frontal 

 border in advance of the glabella ; palpebral lobes a little less than 

 one-third the length of the cranidium; the raised outer margin 

 extends anteriorly across the very narrow space between the anterior 

 end of the eye lobe and the glabella, and thus forms a very short 

 palpebral (ocular) ridge. 



Free cheeks large and rising gradually from the groove within the 

 outer border to the base of the elongate, narrow eye lobe ; their most 

 marked character is the system of strong, irregular inosculating 

 ridges that radiate from the base of the eye outward to the intra- 

 marginal furrow. 



Thorax with nine transverse segments that are all of nearly the" 

 same transverse length ; axial lobe convex and marked by a minute 

 median tubercle as described above in connection with the occipital 

 ring; pleural lobes nearly flat with each segment terminating 

 abruptly, the postero-lateral edge having a very short, blunt spine ; 

 pleural furrows broad and occupying nearly the entire width of the 



The glabella is very much like that of Bathyuriscus, see plate 46. 



