150 



Contributions to Palazontoiogy . 



anterior edge, and converging on the posterior margin 

 from the middle to the extremities. Dorsal furrows 

 strongly but not abruptly impressed at the sides, and at 

 the anterior angles of the glabella : the groove in front 

 of the glabella is more shallow than at the sides. 



Fixed cheeks rising gently from the dorsal furrow, mode- 

 rately convex, not as high as the glabella. Posterior 

 limb with a well defined furrow : palpebral lobes long 

 reniform, and "separated from the cheeks by a strong 

 sigmoid furrow." Frontal limb about one-fifth of the 

 entire length of the head ; "having a deep transverse 

 groove a little in advance of the middle," with a strongly 

 elevated and rounded or " cordlike" anterior margin. 



Movable cheeks comparatively small, narrow elongate, 

 with a thickened border which is prolonged into a slen- 

 der spine. Eye tubercle large. 



Thoracic articulations of moderate, strength ; having a 

 simple groove which becomes gradually narrower towards 

 the outer end, and dies out at the commencement of the 

 recurving extremities. 



Pygidium subquadrilateral, with strong but slender diver- 

 ging spines from the posterior angles. The axis and 

 lateral lobes, without the expanded border, are semi- 

 circular; the axis somewhat abruptly elevated, with 

 five annulations : lateral lobes with five segments, in- 

 cluding the anterior one. The border extends from 

 the extremity of the anterior segment in a direction 

 nearly vertical, or slightly expanding downwards: the 

 posterior edge of the border extends below the termi- 

 nation of the axis about one-fourth the entire length of 

 the pygidium. 



The measurements of three individuals give following dimensions : 



I. II. III. 

 Length of glabella in front of occipital ring.. .23 in. .46 in. .63 in. 



Width of glabella at base 20 .47 .60 



Width of glabella at apex 13 .28 .37 



Length of frontal limb 09 .15 .18 



Entire length of head 37 .71.91 



