r,T2 



THE AMERICAN NATURALIST [Vol. XLII 



have its headquarters in the area which was covered by 

 the glacial ice; it is possible, perhaps, that it lived 

 through the glacial period in some northern locality which 

 was unglaciated, but cut off from the southern fauna. In 

 this way, it might have been protected from the stress of 

 competition, and when the great lakes were opened up, 

 it found in them a comparatively free field— a field ap- 

 parently not yet populated with anything like the maxi- 

 mum number of species. 



Trichophanes is not precisely typical of Aphre- 

 doderidae; it certainly seems to have some characters 

 resembling those of the Percopsida?, no doubt indicative 

 of real relationship. It is readily recognized by its 

 peculiar scales, which are ultra-ctenoid, with the mar- 

 ginal teeth produced into quite long bristle-like struc- 

 tures. According to Cope, they are "without or with 

 very minute sculpture," but under the compound micro- 

 scope they are seen to be covered with fine concentric 

 stria?. 



Cope's type of Trichophanes foliar urn was obtained by 

 Dr. Scudder, and consists of the anterior half of the fish 

 only. This year my wife found at Station 13 B two prac- 



