28 
LEA ON SOME NEW FOSSIL MOLLUSCS, &c. 
PaLjEoniscus? Leidyiana. Plate 20, figs. 4 and 5. 
I am induced to represent the most perfect, out of some half dozpn fish scales on 
the specimen. One of them is magnified to about four diameters. They all seem to 
belong to the same species. The scales are diminutive, rhomboidal,'serrated on one 
edge, and marked with nearly equidistant strise, which are arrested by transverse 
strise. I name this after my friend Joseph Leidy, M. D. 
In giving the above descriptions, I am aware of the disadvantage arising from the 
want of perfect descriptions: but as these forms are the only ones yet found, that I 
am acquainted with, I have deemed it better to give an exact representation of the 
specimen itself, and to give provisional names, that geologists may be able to 
recognize them when met with again. 
