View the slide show of threatened species that have yet to make it onto the endangered species list.

The U.S. Fish & Wildlife Service and its parent agency, the Department of the Interior, have lately come under fire for their management the Endangered Species Act. Last week a document was leaked that reveals plans to revise the law without prior congressional approval.

While agency officials claim that the proposed changes would improve the act's consistency and clarity, environmental groups contend that they would loosen restrictions on timber and other industries, undermine wildlife protections, and reduce the total number of federally protected species. Within days of the leak, federal investigators sent a report to Congress revealing that a high-ranking Interior Department official has been altering reports written by scientists, effectively weakening safeguards for vulnerable species.

None of it sounds like good news for the plants and animals sheltered by the Endangered Species Act. But what about all the species imperiled but not yet protected? Currently, there are 280 species whose populations appear to be in trouble but remain in limbo, awaiting the government's verdict: to list, or not to list. "It's a huge, long, [bureaucratic] process" that takes years, explains Valerie Fellows, spokesperson for the Fish & Wildlife Service. Currently, two species are proposed for listing, meaning that they are under active consideration; another 278 remain on the candidate list, which is the waiting list for proposal. What are some of these proposed and candidate species?