Description of Figures. 



Fig. 1. Lateral view of the head of a larval Lepidosteus , showing the latero- 



sensory pores, x 6. 

 Fig. 2a. Lateral view of the anterior end of the skull of an adult Lepidosteus. 



showing lateral sensory canals in green, x 2. 

 Fig. 2b. Lateral view of the posterior portion of the same skull, x 2. 

 Fig. 3. Dorsal view of the same, in two sections, 3a and o^i; showing the latero- 



sensory canals in full detail on the right side, but the trunks only of 



the dendritic systems on the left side, x 2. 

 Fig. 4. Ventral view of the same, in two sections, 4a and 41». x 2. 

 Fig. 5. Lateral view of the head of a 11 mm larva of Ameiurus nelmlosus. x 12. 

 Fig. 6. Lateral view of the head of a 22 mm larva of Esox americanus. x 10. 

 Fig. 7. Dorsal view of the skull of an adult Ameiurus nebulosus, showing also the 



infraorbital and preoperculo-itiandibular canal bones swung outward and 



upward into the plane of the dorsal surface of the skull, x P/g. 

 Fig. 8. Lateral view of the head of Silurus glanis, showing the lateral-sensory 



canals and head lines of pit organs, x ^|^. 



Dorsal view of the same, x ^j^. 



Ventral view of the same, x '/4. 



Lateral view of the skull of Macrodon trahira, showing the latero-sensory 



canals, x 1^,,. 



Dorsal view of the same, x P/s- 



Lateral view of the skull of Hydrocyon brevis, showing the latero-sensory 



canals, x 2'^/.,. ^ 



Lateral view of the same, x 2'-/.,. 



Lateral view of the skull of Alestes nurse, showing the latero-sensory 



canals, x 2^/3. 



Dorsal view of the same, x 2"/.,. 



Dorsal view of the skull of Carassius auratus, showing the infraorbital 



and preoperculo-mandibular canal bones as in P'ig. 7. x 2-/.,. 

 Fig. 18. Lateral view of the head of Moxostoma aureolum showing the latero- 

 sensory canals and canal bones, x ^/g. 

 Fig. 19. Lateral view of the head of Esox lucius. showing the positions of the 



latero-sensory canals, x ^/3. 

 Fig. 20. Dorsal view of the same, x '/.,. 

 Fig. 21. Ventral view of the same, x ^j^. 



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