298 Wisconsin Academy of Sciences , Arts, and Letters. 
Fig. 1 
Fig. 2, 
Fig. 3 
Fig. 4 
Fig. 5 
Fig. 6 
Fig. 7, 
Fig. 8 
EXPLANATION OF PLATE XXXIII. 
C. americanus Marsh (?). No. 565. Caudal stylet X 295. 
No. 565, external armature terminal joint of inner branch of 
4th swimming foot X 295. 
C. americanus Marsh (?). No. 784. Caudal stylet X 295. 
No. 784, external armature terminal joint of inner branch of 
4th swimming foot X 295. 
C. brevispinosus Herrick, 4th swimming foot X 295. No. 20. 
C. americanus Marsh, 4th swimming foot X 295. No. 1501. 
C. brevispinosus Herrick. Furca X 167. Extreme type. No. 22. 
C. americanus Marsh. Furca X 165. Extreme type. No. 1502 
