EXPLANATIONS OF PLATES. 



PLATE I. 



Necturus mamilatus, skeleton from below, two-thirds natural size 



PLATE II. 

 Necturus maculatus, natural size. 



Fig. 1. Skull, superior view. 



2. Skull, inferior view. 



3. Skull, left side, exterior view. 



4. Skull, left side, interior view. 



5. First and second vertebrse, from below. 



6. First and second vertebr;©, from above. 



7. First and second vertebrae, right side. 



8. Atlas, from front. 



9. Second vertebrae, from behind. 



PLATE III. 



(Copied from Wiedersheim's Kopfskelet der Urodelen.) 



Fig. 1. Necturus maculatus, skull, from below, displaying the chondrocranium of 

 one side. 



2. Necturus maculatus, skull, from above, displaying the cartilaginous nasal cap- 



sules. 



3. Cryptohranckus allegheniensis, skull, left side. 



4. Cryptohranckus allegheniensis, skull, from above, showing chondrocranium of 



one side. 



5. Cryptohranchus allegheniensis, skull, from below, showing cartilages of one side. 



PLATE IV. 



Necturus maculatus, two-thirds natural size, from below, showing viscera, mostly in 

 place ; the alimentary canal and corpus adiposum displaced to the right 

 side of the animal. 



PLATE V. 



Cryptohra7ichus allegheniensis, skeleton, from above, half natural size. 



PLATE VI. 

 Cryptohranchus allegheniensis, skeleton, from below, half natural size. 



PLATE VII. 



Cryptohranchus allegheniensis, viscera from below in position, two-thirds natural size. 

 Drawn by Prof. S. F. Baird. a, auricle ; v, ventricle of heart ; L, liver ; 

 m, mediastinum; s, stomach; i, intestines; o, oviduct; o^, fontanelle of 

 oviduct ; g, gall-bladder ; r, rectum ; c, urinary bladder. 

 1951— Bull. 34 32 497 



