Cope.] ~ 530 [Nov. 18, 



to those of Saurodon; but tlie margins of both, jaws are without the 

 large foramina so prominent in both the other genera. There appear to 

 be some important diflferences also in the vertebra3, which will be men- 

 tioned below. 



In the Transactions of the American Philosophical Society for 1856, 

 Dr. Leidy treats SaurocepJialus as & Sphyrsenoid fish, and regards Sau- 

 rodon as a synomyme. He corrects the erroneous references of some 

 European authors, showing the Saurocephalus of Dixon to be a Xiphias, 

 and the Saurodon of Agassiz to be some other genus which he calls 

 CimolicMliys, without characterizing it. This form is supposed to be 

 established on palatine teeth, and if so, is well distinguished, as it will 

 be seen below, that Saurocephalus has no teeth on the palatine bones. 

 He also refers two other species of supposed Saurocephalus of Agassiz 

 to a new genus called ProtospTiyrcena, without characters. This I think 

 rests on mandibular teeth of true SaurocepJcali. 



SArROCEPHALUS. Harlan. 

 Journ. Acad. ISTat. Sci. Phila. III. 337. XipJiaciinus Leidy Proc. Ac. 

 Nat. Sci. Phil. 1870. 12. 



Saurocephalus lanciformis. Harlan 1. c. 



Med. and Phys. Researches, 3G2. Leidy Trans. Amer. Philos. Soc. 

 1856. Tab. Saurodon lancifoxmis, Hays Trans. Amer. Philos. Soc. 1830, 

 476. 



Established on a right superior maxillary bone from a locality near the 

 Missouri river. It dififers from that of the other species in having a very 

 elongate superior suture with the premaxiUary bone, and in the very 

 short dental crowns, which are as wide as deep. The largest species; 

 known from the jaw. 



Saurocephalus phlebotomus. Cope sp. nov. 



Established on some vertebrae and portions of the cranium, the latter 

 includins: the dentary, maxillary, part of the premaxiUary, the palatine 

 and vomerine bones, compressed into a mass by pressure, the separate 

 pieces preserving nearly their normal relations. From the latter the fol- 

 lowing characters may be derived : 



Palatine bones toothless ; teeth of both maxillary and dentary, with, 

 compressed crowns, which are longer than wide at base, and closely placed, 

 those of the dentary twice as large as those of the maxillary. Maxillary 

 bone proximally deep ; dentary shallower, the maxillary with elongate 

 suture with the premaxiUary behind. 



The teeth are equilateral, without intermarginal groove or barb, and 

 with smooth enamel surface, or only minutely striate under the micro- 

 scope. A series of larger foramina extends along the alveolar margin of 

 the maxillary and dentary bones, one foramen to each tooth. The alve- 

 ola are confluent as they approach this margin. 



There are three vertebrae, which present two pairs of deep longitudinal 

 grooves, viz. : two on each side, two on the inferior, and two on the supe- 



