4r^ nO\\^^ /contents * 



V\mation in Nacreous (^or of Certain Species of Naiades Inhabiting 

 ^^he UDoer O^i^pj'Sinage and their Corresponding Ones in Lake 



Ene:* (riaLTr trn, III.).— iV. M. Grler, Ph. D 211 



Dr. Joel Lunell (Frontispiece) — 243 



Waterfowl in Nebraska — Brother Alphonsus, C. S. C 245 



Variation in Epidermal Color of Certain Species of Najades Inhabiting 

 the Upper Ohio Drainage and their Corresponding Ones in L. Erie. 



—N. M. Grier, Ph. D ...._ ....._ _..._ 247 



Observations on Some Marine Plants of the Iowa Devonian, With De- 

 scriptions of New Genera and Species. — Clement L. Webster, M. Sc... .286 

 Birds Observed at Brookland, D. C. from Aug. 19 to Sept. 7, 1920. — 



Brother Alphonsus, C. S. C 290 



