Lewis Carroll himself gave conflicting descriptions of toves, raths, and perhaps other critters. Before writing Looking Glass, he wrote a periodical called Mischmasch, in which he may have given the description you mention. But in Looking Glass, Humpty Dumpty gives some different descriptions. Slithy_Tove’s avatar follows Humpty Dumpty’s definition and agrees with Tenniel’s illustration:
To be sure, the Wikipedia page for Jabberwocky seems garbled: At one point, it says: