You can see the phenakistoscope DEMONSTRATED (that's the word I was looking for in this morning's lecture!) on YouTube in many different videos. Here's one that gives you an idea of what the device accomplishes. Enjoy.
More info about Muybridge and how he studied horse locomotion is available at this link: http://www.horselocomotion.com/horse_motion_capture_data_faq.html . WARNING: nudity. Not for the faint of heart.