This fish, which must now be known by the name of Macrope- 

 talichthys, is not only of interest to the paleeontologist and zoolo- 

 gist as the most characteristic vertebrate of the epoch of the Cor- 

 niferous Hmestone on this continent— the ganoid monarch of our 

 Devonian seas,— but also as furnishing additional evidence of the 

 parallelism of our lower Devonian strata with the limestones of 



the Eifel; for a species of 



i of ours, has been discovered in that formation and locality 



probably identical with 



and is described and figured by the distinguished palaeontologist 

 Hermann von Myer, (Palseontographica, vol. i, p. 102, T. xii). 



By von Myer this fish was referred to the genus Placoihorax 

 of Agassiz, but as I have shown in the paper read before the 

 -National Institute, von Myer, misled by the distortion of his 

 specimen, has mistaken the occipital for the nasal extremity of 

 the cranium ; and further that it could not be included in Placo- 

 woroa;, but must be referred to another genus and another family. 

 A he present state of our knowledge of this genus may be com- 

 prehended at a glance from the following description and figure. 

 Genus Macropetalichthys, Owen. 



Agasskhthys, Newb. 



Placothoraoc, v, Myer, not of Agassiz. 

 -Desc. —Ccelacanth ganoids of Isltsq size, cranial surface cov- 

 ered with thickly set stel- 

 late tubercles in lines 

 radiating from various 

 centres, or without regu- 

 w arrangement. Cra- 

 nium composed of large 

 plygonal plates united 

 by double sutures which 

 are nearly concealed by 

 tlietubercled enamel sur- 

 lace. Eye orbits conspic- 

 uous and included in the 

 orbital plates. Teeth in 

 two rows, conical, curv- 

 e*^, acute, smooth, not pli- 

 cated at base nor dendri- 

 tic m structure. Scales 

 Obscurely rounded, the 

 ^^Posed portion orna- 

 mented with small tuber- 

 ^es and fine divergent 

 S^sed lines, the cover- 

 all portion marked with 

 "les of growth, and fine- 



