As a symbol, the crocodile can have a wide variety of meanings. It can be the 'devourer.' It can represent the necessity of passing through death to life. As a crocodile both lives on land, and in the water, it denotes the dual nature of man.
In Egyptian Mythology, and in Aleister Crowley's Toth Tarot Deck, a crocodile is a representation of the God of Creativity. (Cf. cards # 0 and X of the Major Arcana).