Iv.t8-10(>2. No. 33.1 UPPER DEVONIAN FISH RE^[AINS. 13 



Comparison With Forms Known Previously. 



The folidwin;^ species of tliis t;eiiM^ have been desci'ibeil previnuslv: 

 1. MacropetaUchtliys raplicidolahis Nor\y. AL' Owen. 



The be.st known form of which a number of specimen.s have been 



found in Onondaga Lime.slone in New York, Columbus and Dela- 



wai'e Lmst. in Ohio. Corniferous Limestone in Indiana and Canada!?), 



that is in horizons of Middle Devonian age. 

 2. Macropetalichthys Agassui \. Meyer. 



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



steiu, Eifel; the original i.s at Cambridge, Mass. 

 o. Macropetalichthys Prilmiensis Kayser. 



One specimen, somewhat defective, from the Upper Lower Devonian 



at Priim, Eifel; the original is at Berlin, 

 4. MacropetaUchtliys pelinensis Hennig. 



One specimen, of poor qualilv. from the Upper Middle Devonian at 



Pelm, Berlingen. Original is at Berlin. 



I' inally, Jaekel has announced the discovery of a Macropetalichthyid 

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

 The original, which is at FiankfortonMain, has not yet been fully described. 



Li 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, MacropetaUchtliys 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 NoBW. & Ow. . . 48" — 49" 



— Agassisi 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 

 Prilmiensis and agrees with Agassisi v. Meyer, and possibly Pelmensis 

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

 new form is nearest to M. Agassisi v. Meyer, but differs from the 

 latter at important points. 



