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 Geoft’. St. Hilaire 
Drawing by Anna L. Brown. 
3. Petromyzon marinus Linnjeus 10 
Drawing by H. L. Todd from No. 10654, U.S.N.M., collected at 
Woods Hole, Massachusetts, by Y. 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. 
5. Lampetra aurea (Bean) 13 
Drawing by H. L. Todd from No. 21524, U.S.N.M., collected by 
Lucien M. Turner in the A^ukou Eiver, Alaska. 
6. Lampetra spadicea Beau 13 
Drawing by H. L. Todd from the tyjie specimen. No. 38005, 
U.S.N.M., collected by Prof. A. Dug^s 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. Hexanchus 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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