Estimation of evaporation from farm ponds. R.H. Shaw and Yi-Ming Yao 349

Leguminosae of the north-central United States III. Mimosoideae and Caesalpinioideae. Duane Isely 355

Some simple mathematical models as aids in interpreting the effect of fishing. Kenneth D. Carlander 395

The plankton of North Twin Lake, with particular reference to the summer of 1955. Joseph H. Kutkuhn 419

The solubility of water vapor in fused alkali nitrate mixtures and n lithium perchlorate. Frederick R. Duke and Arthur S. Doan, Jr. 451

Transamination in Priopionibacterium jensenii. R.W. Kinney an C.H. Werkman 455

Measurement of magnetic field gradients by the Hall effect. R.W. Redin and G.C. Danielson 463