Stewart.] Cretaceous Fishes, 363 



this time, moreover, an important addition to our knowledge of 

 the species was rendered possible by a fine fossil in Sir Philip 

 Egerton's collection, which showed that the fish had a remark- 

 ably elongate snout. Six years afterwards Professor Leidy 119 

 carefully reexamined Doctor Harlan's original American speci- 

 mens of SaurocepJialus, and soon became convinced that Agassiz 

 was mistaken in supposing that the English fossils were identi- 

 cal with these even generically. He thus proposed a new ge- 

 neric and specific name — Photosphyra naferoz — for the specimens 

 figured by Man tell, Agassiz, and Dixon ; wrongly suggesting, 

 however, that Sir Philip Egerton's fossil rostral bone truly be- 

 longed to a swordfish, which might be appropriately termed 

 Xiphias dixoni. Between 1875 and 1877 remains similar to those 

 of the English Chalk were actually discovered in America, and 

 not only proved that Egerton and Dixon were right in deciding 

 upon the reference of the long snout to Protosphyr8sna } but 

 further added important anatomical details. Professor Cope,, 

 however, who described these fossils, 120 proposed the difficultly 

 pronounceable name of Erisichthe, which happily becomes a 

 synonym." 



The frontals of this genus are broad and flat, and are more 

 or less covered with short corrugations. Anteriorly they unite 

 with the ethmoids, which, with the prefrontals, vomer, and 

 parasphenoid, form the long and pointed rostrum mentioned 

 above. The frontals form the superior boundary of the orbits, 

 which are large and surrounded by a ring of sclerotic bones. 

 The pterygoids are covered with small, conical teeth, thickly 

 set, and elevated upon small, bony hemispheres. The meso- 

 pterygoid is a broad and thin bone, covered with teeth similar 

 to those found on the pterygoid. The upper jaw is composed 

 of the maxilla and premaxilla. The first of these is slender 

 and bears two rows of teeth, the inner of which is composed of 

 large teeth with anterior and posterior cutting edges, eacli of 

 which is set in a separate alveolus. The outer row is composed 

 of small, conical teeth united directly with the bone. The 



110. Tran~. Am. Phil. Soc., vol. XI, 1860, pp. 91-95. 



120. Cret. Vert. West, pp. 217, 218, and Bull. U.S. Geol. Surv. T^rr.. vol. Ill, 1877, pp. 821-82:1. 



