►62 University Geological Survey of Kansas. 



PACHYCORMIDJE. 



Pelecopteridce Cope. Erisichtheidce Cope. 

 Protosphyrcenidce Woodward. 



This family is very peculiar in having the ethmoid bone pro- 

 longed into a long rostrum or beak, and includes the single 

 American genus Protosphyrssna. For a long time this form was 

 not well understood, as Professor Cope described the pectoral 

 fins as belonging to the genus Pelecopterus , and the cranial por- 

 tions to the genus Erisichthe, from which arose the family names 

 of Pelecopterid&e and Erisichtheidse. It was later discovered that 

 these two genera were one and the same, and also that they 

 were synonyms of the genus Protosphyrsena , which was described 

 by Leidy several years before. 



PROTOSPHYR^NA. 



Protosphyrcena Leidy, Trans. Am. Phil. Soc, vol. XI, pp. 91-95. 



Xiphias Leidy, Trans. Am. Phil. Soc, vol. XI, pp. 91-95. 



Erisichthe Cope, Proc. Acad. Nat. Sci. Phil., 1872, p. 280. 



Pelecopterus Cope, Cret. Vert. West, p. 244 C. 



114 <<The teeth are laterally compressed and lanciform, with- 

 out marginal serrations, and, when found in connection with 

 the jaw, are seen to be fixed in distinct sockets. They were first 

 noticed in 1822 by Doctor Mantell, 115 who described one example 

 as belonging to an unknown fish, and referred a second to an 

 undetermined species of shark. Twenty-one years later Profes- 

 sor Agassiz studied the fossils, and thought that they were most 

 probably identical with certain teeth discovered by Doctor Har- 

 lan 116 in the Cretaceous strata of North America, which had been 

 described under the name of Saurocephalus lanciformis , and 

 erroneously placed among the Reptilia. They were accordingly 

 made known as such in the great work on the " Poissons Fos- 

 siles/' 117 and the determination was subsequently adopted by 

 Dixon, 118 in 1850, who figured more satisfactory specimens. At 



114. A. S. Woodward, Proc. Geol. Assoc, vol. X, 1888, pp. 320, 321. 



115. Foss. South Downs, p. 227, pi. XXXIII, figs. 7-9. 



116. Jour. Acad. Nat. Sci., Phil., vol. Ill, 1824, pp. 331-337, pi. XII, figs. 1-5. 



117. Poiss. Foss., vol. V, pt. I, p. 102, pi. XXVc, figs. 21-29. 



118. Foss. Sussex, p. 374, pi. XXX, fig. 21 ; pi. XXXI, fig. 12 ; pi. XXXII, fig. 1 ; pi. XXXIV, fig. 2. 



