The word carcasses is easily to be understood out of Leviticus 11:24,25, where it is expressed.
Related Commentaries of Leviticus 11:26
Leviticus 11:26
26 The carcases of every beast which divideth the hoof, and is not clovenfooted, nor cheweth the cud, are unclean unto you: every one that toucheth them shall be unclean.