187 



centrum. In the third vertebra the parapophyses are high up, as in the first- 

 described specimen. In the succeeding two they spring from near the middle 

 of the sides of the centrum. 



The measurements of the second cervical are as follows : 



Lines - 



Length of centrum inferiorly 4 



Depth of centrum anteriorly 13 



Breadth of centrum at middle 20 



The measurements of the fifth vertebra are as follows : 



Lines. 



Length of centrum inferiorly 3. 



Depth of centrum anteriorly . 12. 



Breadth of centrum at middle, on line with parapophyses 17. 



A series of three posterior dorsal centra, from the same locality as the 

 preceding specimens, perhaps belong to the same species, but, from their 

 appearance, most probably to another individual. They are somewhat dis- 

 torted from pressure, and appear in the original condition closely to have 

 resembled corresponding vertebrae of Amia calva, but are nearly three times 

 the breadth, and scarcely twice the length. 



The three specimens together, represented in Fig. 5, measure 16 lines in 

 length. 



The anterior of the three presents the following measurements : 



Lines. 



Length of centrum inferiorly 5 



Depth of centrum anteriorly 11 



Breadth of centrum inferiorly, opposite the diapophyses 14 



A specimen from Dry Creek, consisting of a mutilated basi-occipital, about 

 the size of that of the alligator-gar, differs considerably as well as from that 

 of the mud-fish. It is represented in Figs. 6, G a , and may perhaps belong to 

 Protamia. 



The articular conical cup has its acute margin scolloped, as seen in Fig. 6. 

 The deep median groove on the under part of the bone in Amia and Lepi- 

 dosteus reaches the articular margin, but in the fossil, stops the fourth of an 

 inch short of it. On each side of the bone at the articular margin corresponding 

 with the lateral notch there is a conspicuous fossa not seen in the genera just 

 named. In advance of the fossa on each side of the median groove there is 

 abroad, slanting, flat surface, longitudinally ridged, of which there is likewise 

 no exact counterpart in Lepidosteus, but appears to correspond with a smooth 

 surface occupying the same position in Amia. 



