Meta Ontology

Kripke claims that certainkind terms, particularly natural kind terms,are, like names, rigid designators. However,kind terms are more complicated than names aseach is connected both to a principle ofinclusion and an extension. So, there is aquestion regarding what it is that rigidlydesignating kind terms rigidly designate. Inthis paper, I assume that there are rigidlydesignating kind terms and attempt to answerthe question as to what it is that they rigidlydesignate. I then use this analysis of rigidlydesignating kind terms to show how Kripke''sreasoning regarding the necessity of `Hesperusis Phosphorus'' can be extended to statementsinvolving kind terms like `Water is H2O''and `Tigers are mammals''.