EXPLANATION OF PLATE. 



Fig. L The Common Perch. {Perca flaveacens.) 

 A. Anal fin. 

 C. Caudal fin. 

 I. Op. Interopercle. 

 M. Maxillary. 

 Op. Opercle. 

 P. Pectoral fin. 

 P. M. Premaxillary. 

 P. Op. Preopercle. 

 P. Orb. Preorbital. 

 S. D. Spinous dorsal fin. 

 Sfd. D. Soft dorsal fin. 

 S. Op. Snbopercle. 

 Y. Ventral fin. 



Fig. II. Head of a Calico Bass. {Pomoxis sparoides.) 

 S. M. Supplemental maxillary bone. 



Fig. III. Common Bed Horse Sucker. (Moxosioma aureolum.) 

 Isth. Isthmus. 

 G. U. Gill membranes united to the isthmus. 



Fig. IV. The Common Perch dissected so as to show some of the internal organs. 

 A. B. Air-bladder. 

 G. Gills. 

 G. B. Gill-rakers. 

 I. Intestine. 

 P. C. Three pyloric cseca. 

 S. Stomach. 

 U. B. Urinary bladder. 



