I02 NEW YORK STATE MUSEUM 



men sis by Dr E. Kayser.' It was further described and illustrated by 

 Professor A. von Koenen in 1895, together with an imperfectly preserved 

 Bohemian cranial shield, designated as Holopetalichthys novaki. 

 Quite recently, as we have already seen, Dr Otto Jaekel expressed the 

 opinion that the type of M. pruemensis should be held to represent a 

 distinct genus. 



We may now trace the progress that has been made in investigating 

 the typical American species, which had not ceased to attract attention. 

 Professor Newberry contributed to the first number of the Annals of 

 Science, published October 15, 1852, a brief account of " Fossil Fishes from 

 the Cliff Limestone," in which he described and figured an unusually per- 

 fect specimen of Macropetalichthys. Although the position of the principal 

 plates and their centers of ossification are clearly portrayed in this early 

 woodcut, the significance of these features was not understood, and no 

 account was taken of them in later restorations. Newberry's views as to 

 the relations of his fossil are thus stated : " This is evidently the cranium 

 of a ganoid fish, allied to the Asterolepis of Europe, and is probably identical 

 with that described by Owen and Norwood. I ssiy probably, for although 

 the general outline of the cranial plates seems to establish an identity, 

 their description would indicate entire distinctness — a discrepancy which I 

 am inclined to attribute to the imperfect preservation of their specimen." 



Other crania were exhibited by Newberry before the American Asso- 

 ciation for the Advancement of Science at the Cleveland meeting in 1853, 

 and in 1857 descriptions were given of two new species, the so called 

 "Agassichthys sullivanti and A. m a n n i," which were at that time 

 considered to be generically distinct from Macropetalichthys." A few years 

 later, however, Newberry returned to the belief that the two species of 

 "Agassichthys," and also the type of von Meyer's " Placothorax," all 

 belonged to Norwood and Owen's genus.^ Subsequently he found it diffi- 



' Zeitschr. deutsch. geol. Ges. 1880. 32:678. 

 ^ Nat. Inst. Bui. 1857. p. 119-24. 

 3 Am Jour. Sci. [2] 1862. 34: 74, 75. 



