Those look consistent with Gray Treefrog tadpoles. Even from the same batch of eggs they can get to land a few weeks apart.

Here are some tadpole ID links. Take a look at eye terminology from the 'tutorial' link below, then head to the 'small chart of common tads'. Lateral vs dorsal eyes is a quick way to rule out bullfrog and add confidence these are also Treefrogs.

A complex tadpole key: USGS Patuxent Wildlife Research Center "Tadpoles of the United States and Canada: A Tutorial and Key"
The tutorial for the above key (explains the anatomy bits): North American Tadpoles
A small chart of common tads: Tadpole Identification Table
The SEARMIT tadpole guide: http://fl.biology.usgs.gov/armi/Guid...dpoleGuide.pdf