Fig. 1.--Section of the seed coat of _Melilotus officinalis_. × 450. Fig. 2.--Another section of the seed coat of _Melilotus officinalis_, showing the variation in size and modifications that occur in the three layers. × 450. Fig. 3.--Section of the Malpighian layer of a _Melilotus alba_ seed, showing a line of canals just above the light zone. × 450. Fig. 4.--Section of the Malpighian layer of a permeable _Melilotus alba_ seed. × 450. Fig. 5.--Tangential section of the Malpighian cells cut between the cuticle and tops of the cones, showing pores. × 530. Fig. 6.--Section through the Malpighian layer of an impermeable _Melilotus alba_ seed. × 450. Fig. 7.--Section through the Malpighian layer of an impermeable _Melilotus alba_ seed, showing the region through which water and stains readily passed. × 450. Fig. 8.--Cross section of a Malpighian cell of a permeable _Melilotus alba_ seed through the region of the light zone, showing the lumen not entirely closed. × 530. Fig. 9.--Section through the Malpighian layer of a _Melilotus alba_ seed shaded to show the portions which react to the cellulose and pectose tests. × 450. Fig. 10.--Section through the Malpighian layer of a _Melilotus alba_ seed which shows the condition of the seed coat after 60 minutes' treatment of concentrated sulphuric acid. That portion above the light zone was destroyed, and the lumina as small pores through which much of the stain now passed were seen extending across the light line. The lines between the cells were much more distinct, appearing as small intercellular spaces through which some stain passed. × 450. _a_, Cuticle; _b_, cuticularized layer; _c_, conelike portion of the thickening of the Malpighian cells; _d_, light line; _e_, region of a hard seed coat through which water and stains readily passed; _l_, lumen; _M_, Malpighian cells; _N_, nutrient cells; _O_, osteosclerid cells; _p_, canals just above light zone. MICROCHEMISTRY OF THE SEED COAT. Tests for cutin showed that there was very little present in the seed coat. Slight reactions for cutin were observed in the cuticle, in the outer margin of the cuticularized layer, and in the basal portion of the cones. These reactions were so slight as to be almost negligible. It is evident that the cuticle and cuticularized layer are not well named in _Melilotus alba_ and _M. officinalis_. Tests for cellulose showed that it was present in the cuticle, cuticularized layer, cones, the walls of the Malpighian cells below the light line, and the walls of the cells of the osteosclerid and nutrient layers. (Pl. V, fig. 9.) The reaction for cellulose in the Malpighian cells was quite distinct in the walls below the light line, less distinct in the cones and cuticle, and least distinct in the cuticularized layer.