12 



PISCES. 

 ACTINOPTBRYGII. 



Amia whiteavesiana, Cope. 



Amia xchiteavesiana, Cope, 1891. The species from the Oligocene or Lower Miocene beds 

 of the Cypress hills. Geol. Survey of Canada, Contr. to Can. Palreont., vol. Ill (quarto), 

 pt. I, p. 2, plate I., figs. 1, la and 16. 



No remains of this species were obtained by the writer in his expedition of 1904 to the 

 Cypress hills. The type of this species, as well as those of all of the species referred to or 

 described in the following pages, are in the Museum of the Geological Survey at Ottawa. 



Amia macrospondyla, Cope. 



Amia macros pondy la, Cope, 1891. The species from the Oligocene or Lower Miocene beds 

 of the Cypress hills. Geol. Survey of Canada, Contr. to Cau. Palreont., vol. Ill (quarto), 

 pt. I, p. 2, plate I, figs. 2, 2a and 26. 



Cope established this species on a single vertebra from the Cypress hills. No additional 

 material is included in the collection of 1904, to throw further light on the structure of 

 this fish. 



Amia exilis, Sp. nov. 

 Plate I, figs. 1-6. 

 A number of centra, found separately, represent an apparently undescribed species 

 of Amia, of small size as compared with A. whiteavesiana, Cope, and A. macrospondyla, Cope 

 both of which species are from the Oligocene of the Cypress hills. 



All the fossil remains of North American species of Amia so far described are of Eocene 

 age, with the exception of the two Oligocene species above mentioned. 



Amia exilis was about the size of Amia elegans, Leidv, from the Bridger Eocene of 

 "Wyoming ; but had vertebral centra of quite a different shape. 



The centra on which Amia exilis is founded are mostly from th.e dorsal region, and vary 

 somewhat in size, being probably from a number of individuals. The one represented on 

 plate I, figures 1, 2, and 3, from the middle dorsal series, is one of the largest of the 

 specimens, and is about the best preserved (type). Its articular faces are oval in outline 

 with the major axis horizontal, the height being but slightly over two-thirds of the 

 breadth. Its thickness (length), is equal to about half the maximum height and there is a 

 perceptible flattening of the upper surface. The concave articular surfaces exhibit a few 

 concentric lines, but have the general appearance of being rather smooth. A small notochordal 

 foramen, preserved in all the specimens, pierces the centrum at about mid-height. Above, 

 in the median line of the upper surface, the floor of the neural canal appears as a narrow, 

 oblong, transversely concave depression, with a shallowly excavated area, square in outline 

 on each side of it, marking the position of the base of the neurapophysis. The parapophyses 

 are placed slightly below the middle of the sides ; they are circular in section and were 



