I'm going to guess that they are Wood Frogs, Rana sylvatica. Gold flecks, transparency, tail pattern, and time of year are making this my guess. They eyes also look like they're dorsal, but I could be wrong. This is a wood frog tadpole:


Wood Frog Tadpole by Jelly Brain, on Flickr

It hit land about 4 weeks after this stage, so no matter what I'd expect you'll have an easy ID in a few weeks.

Some handy ID links:

Your state frogs/toads: Discover Maryland's Herps - Wildlife and Heritage Service - Maryland Department of Natural Resources
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


150 of anything will be tough to raise- I'd look to send most of them out as soon as their tails are absorbed. Make absolutely sure that once the front legs start to 'pop', ideally a little before just in case you miss it, that they have an easy way out of the water. They like to drown themselves when transitioning.

Anyway, good luck with your charges!