PLACOGANOIDEI 119 



fishes of the extinct order Placoganoidei were first discovered 

 about 1813, in formations of the "old red" or Devonian age 

 in Russia, and are preserved in museums at St. Petersburg and 

 Dorpat. The relation of these specimens to the class of fishes 

 was first announced by Professor Asmuss,* and shortly after, 

 the generic names Asterolepis and Bothriolepis were invented 

 by Professor Eichwald,f to express certain modifications of 

 the external surface of portions of the ganoid plates, subse- 

 quently recognised as constituting the buckler of the fore-part 

 of the extinct fishes. In September 1840 Mr. Hugh Miller 

 submitted to the geological section of the British Association 

 at Glasgow the first discovered specimens, affording a recog- 

 nizable idea of the form of one of these " old red" fishes, and 

 for this form Professor Agassiz assigned the generic name 

 Pterichthys (pteron, a wing, ichthys, a fish). Although, there- 

 fore, the term Asterolepis had been attached to a fragment of 

 the cuirass of this fish a few months previously, yet, as no recog- 

 nizable generic characters were associated with such name, 

 and as Asterolepis has been applied also to other genera 

 — e. y., Homosteus and Heterostius of Asmuss — the example of 

 British palaeontologists will be here followed, in retaining the 

 name Pterichthys for the present genus. " Of all the organisms 

 of the system," wrote the lamented Hugh Miller in his work 

 on the Old Red Sandstone, " one of the most extraordinary, 

 and the one in which Lamarck would have most delighted, is 

 the Pterichthys, or winged fish, an ichthyolite which the writer 

 had the pleasure of introducing to the acquaintance of geolo- 

 gists nearly three years ago (1840), but which he first laid 

 open to the light about seven years earlier" (1833). 



Genus Pterichthys (fig. 43). — The head and the anterior 



* Bulletin Scient. par I' Acad. Imp. des Sciences de St. Petersburg, 1840, 

 t. vi., p. 220. 



f Ibid, t. vii., p. 78, communicated Marcli 1"., 1840. Dr. Fleming had 

 recognized certain fossil scales as those of fishes in the "Old lied" el' Fife 

 shire, in 1827. 



