Myriad supports Notification Center. By default, Notifcations are shown as Alerts.

If you wish to change them to Banners, do the following:

  1. Choose System Preferences from the Apple menu
  2. Click Notifications
  3. Choose Myriad in the list

To learn more about Notifcations in OS X, read this Apple Support article:

Mac Basics: Notifications keep you informed