GINGLYMODI. 53 



CLASTES Cope. 



Annual Report U. S. Geol. Surv. Terrs., 1872 (187.3), p. 633. American Naturalist, 1878, p. 761. 



Mandibular ramus, without or with reduced fissure of the dental for- 

 amen, and without the groove continuous with it found in Lepidosteus. One 

 series of large teeth, with small ones exterior to them in the dentary bone, 

 the inner superior aspect of that bone without prominent dentiferous or 

 rugose rib. 



An inspection of French specimens, probably belonging to this genus, 

 has shown that the maxillary bone is much less segmented than in Lepidos- 

 teus, if it be divided at all. The characters o£ Clastes were originally derived 

 from the under jaw, and I have observed them in two species, one which I 

 suppose to be the Lepidostens gldber Marsh, and the other L. atrox Leidy. 



Tlie species of this genus resemble in many ways the Lepidostei of the 

 present day. Their scales are rhombic and pierced by a duct on the lateral 

 line. The cranial bones are ornamented by tubercles of ganoine, distrib- 

 uted variously, according to the species. Some of these fishes reached a 

 large size, exceeding any now living, othei's resemble the true Lepidostei in 

 this respect. 



The first indication of the occurrence of gars in our Western Tertiaries 

 was furnished by Professor Marsh, who announced his discovery of them 

 before the Academy of Philadelphia (Proceedings 1871, p. 105). He named 

 two species, but did not give any descriptions, excepting so far as the 

 statement that one of them has "unusually short vertebrae," and that the 

 other has them " proportionally longer," maybe regarded as such. Under 

 these circumstances I have been unable to identify the species referred to, 

 and think that the names proposed for them by Marsh cannot be used. 



Clastes anax Cope. 



Annual Eeport U. S. Geol. Sui-v. Terrs., 1872 (1873), p. 633. 

 Plate II, figs. 50-52. 



Represented by some cranial bones and especially by a post-temporal, 

 which indicate a very large species of gar, two or three times as large as 

 the alligator gar of the Mississippi, (Litholepis ferox). The bone has a 



