114 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 



low median notch. Five pairs of shallow, broad pleural furrows end 

 very sharply on the line corresponding to the margin of the doublure. 

 The remaining portion of the pleural regions is smooth and flat or 

 slightly concave. Surface of test smooth. Length of largest pygidium 

 6 mm., width 10.7 mm. 



This pygidium may belong to Coosia or a related trilobite. It differs 

 from the usual pygidia of Coosia in the great relative length of the axis. 

 No corresponding cranidium was collected. 



Occurrence. — Upper portion of lower limestone member of the Noli- 

 chucky (Crepicephalus zone) at locality cnm/2. One specimen was col- 

 lected from the lower portion of the same limestone at locality cnk/1. 



Disposition of material. — Figured specimens : U.S.N.M. 144732. 



