(A) Representative resting WF rat platelets prepared identically to resting Wistar platelets in Fig 2. (B through E) WF rat platelets allowed to adhere to Formvar-coated, carbon-stabilized grids from 30 seconds to 30 minutes, and subsequently fixed and stained with uranyl acetate. (B through E) illustrate the forms characteristic of WF rat platelet spreading, including platelets with stubby filopodia (B), lamellipodia (C), or fully spread forms (D and E). (E) shows the spread margin of a WF platelet at higher power. The arrowheads indicate microtubules and the asterisk shows the dense peripheral weave at the platelet margin. (B) 30-second adherent sample, (C) 1-minute adherent sample, (D and E) 30-minute adherent sample. (A through D, original magnification ×7,000; E, original magnification ×19,000).