189 

 HYPAMIA. 



Hypamia elegans. 



Figs. 19 to 22, Plate XXXII, represent a vertebral centrum, found by Dr. 

 Carter on Dry Creek. It is from near the middle of the dorsal series, and 

 evidently indicates a genus distinct from but nearly related with Amia. As 

 hi tliis, the centrum is short in proportion with its breadth, and it presents 

 sutural impressions for a contiguous pair of neural arches. The articular 

 cups have their bottom central and minutely perforate. The sides below the 

 parapophyses are concave, and converge to a median prominence, which is 

 excavated into a pair of fossae, separated only by a linear partition. The 

 parapophyses are cylindroid and comparatively short. 



The measurements of the specimen are as follows : 



Lines. 



Length of centrum inferiorly 2. 2 



Depth of centrum anteriorly G. 5 



Breadth of centrum anteriorly - 7. 6 



Breadth of centrum, including parapophyses S. 5 



The specimen indicates a species about one-third larger than Amia calva. 



LEPIDOSTEUS. 



» Lepidosteus ateox. 



During Professor Hayden's expedition of 1870, James Stevenson collected 

 a number of remains of fishes at the junction of Big Sandy and Green Rivers, 

 Wyoming. The specimens consist of isolated vertebral centra, ganoid scales, 

 and portions of jaws with teeth, all of a black hue. Among them are several 

 vertebrae indicating an extinct species of gar larger than the existing alliga- 

 tor-gar, Lepidosteus ferox. 



Figs. 14, 15, Plate XXXII, represent the centrum of a vertebra from a 

 position in advance of the middle of the dorsal scries. The length of the 

 centrum is not greater than the breadth. The extremities are hexahedral in 

 outline. The under surface is flat, and ornate with longitudinal and somewhat 

 reticular wrinkles. The sides beneath the parapophyses are impressed into 

 a deep fossa. The neurapophyses are likewise impressed at the sides with a 

 deep fossn, and a second deep pit occupies a position just behind and above 

 the parapophyses. These appear rather narrower than in the alligator- gar, 

 and are less anterior in position. 



