1898-1902. No. 33.] UPPER DEVONIAN FISH REMAINS. 13 



Comparison With Forms Known Previously. 



The following species of this genus have been described previously: 

 1. Macropetalichthys rapheidolabis NORW. & OWEN. 



The best known form of which a number of specimens have been 

 found in Onondaga Limestone in New York, Columbus and Dela- 

 ware Linst. in Ohio, Corniferous Limestone in Indiana and Canada (?), 

 that is in horizons of Middle Devonian age. 

 Macropetalichthys Agassizi v. MEYER. 



One specimen, somewhat defective, from the Middle Devonian at Gerol- 

 stein, Eifel ; the original is at Cambridge, Mass. 



3. Macropetalichthys Prilmiensis KAYSER. 



One specimen, somewhat defective, from the Upper Lower Devonian 

 at Priim, Eifel; the original is at Berlin. 



4. Macropetalichthys pelmensis HENNIG. 



One specimen, of poor quality, from the Upper Middle Devonian at 



Pelm, Berlingen. Original is at Berlin. 



Finally, JAEKEL has announced the discovery of a Macropetalichthyid 

 form of a new type from the Lower Middle Devonian at Gerolstein, Eifel. 

 The original, which is at Frankfort on Main, has not yet been fully described. 



In the appended figures (fig. 2) I have given a schematic drawing 

 of the new form and of those previously known, which are sufficiently 

 well preserved for the main features to be reconstructed. As will be 

 seen, Macropetalichthys Scheii is here reconstructed in natural size, 

 whilst the others are diminished; the new form is thus much smaller 

 than those known previously. 



It is also distinguishable from them in other ways. One important 

 circumstance is the more or less remarkable divergence of the two 

 supra-orbital canals in front of the commissure. The following table 

 gives the size of the supra-orbital angle in the known species: 



Macropetalichthys rapheidolabis NORW. & Ow. . . 48 49 



Agassizi v. MEYER 39 



Prilmiensis KAYSER 21 



Pelmensis HENNIG ? 



Scheii KLER 39 



We see that in this respect the new form stands just between the 

 short and broad American form M. rapheidolabis and the elongated 

 Prumiensis and agrees with Agassizi \. MEYER, and possibly Pelmensis 

 HENNIG, both from the European Middle Devonian. On the whole the 

 new form is nearest to M. Agassizi v. MEYER, but differs from the 

 latter at important points. 



