EXPLANATION OF PLATES AND FIGURES. 



NOTE. The actual size of the specimen from which each 

 illustration was drawn may, in most instances, be determined 

 by the use of the inch mark beneath the engraving, which, in 

 the photographic reduction of the drawing, is reduced in the 

 same proportion as the drawing itself. 



PLATE I. 



Text page. 



1. Branchiostoma caribaeum Sundeval .. 3 



Drawing by A. H. Baldwin from a specimen in the United 

 States National Museum. 



2. Polypterus bichir Geoff. St. Hilaire 



Drawing by Anna L. Brown. 



3. Petromyzon marinus Linnaeus 10 



Drawing by H. L. Todd from No. 10654, U.S.N.M., collected at 

 Woods Hole, Massachusetts, by V. N. Edwards. 



4. Entosphenus tridentatus (Gairdner) 12 



Drawing by A. H. Baldwin from No. 48204, U.S.N.M., col- 

 lected in Kamchatka by Dr. L. Stejneger. 



PLATE II. 



. Lampetra aurea (Bean) 13 



Drawing by H. L. Todd from No. 21524, U.S.N.M., collected by 

 Lucien M. Turner in the Yukon River, Alaska. 



6. Lampetra spadicea Bean 13 



Drawing by H. L. Todd from the type specimen, No. 38005, 

 U.S.N.M., collected by Prof. A. Duges at Guanajato, Mexico. 



7. Notorhynchus maculatus Ayres 17 



Drawing by H. L. Todd from No. 27191, U.S.N.M., collected 

 in Humboldt Bay, California, by Dr. Jordan. 



8. Hexaiichus griseus (Gmelin) 19 



Drawing by H. L. Todd from No. 37790, U.S.N.M., collected 

 in Currituck Inlet, North Carolina, by D. M. Etheridge. 



PLATE III. 



9. Gyropleurodus francisci (Girard) 20 



Drawing from No. 24977,U.S.N.M., collected at Wilmington, 



California. 

 10. Heterodontus philippii 



Drawing by Anna L. Brown. 



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