typedef PtrToNode List; program defined List implementation

error C2146: syntax error : missing ';' before identifier 'List'

typedef struct Node *PtrNode;
typedef PtrToNode List; //my error is in this part
typedef PtrToNode Position;

struct Node
{
     ElementType Element;
     Position Next;
};

//function declarations
List MakeEmpty(List L);
int IsEmpty(List L);
int IsLast(Position P, List L);
Position Find( ElementType X, List L);
void Delete(ElementType X, List L);
Position FindPrevious(ElementType X, List L);
void Insert(ElementType X, List L, Position P);
void DeleteList(List L);
Position Header(List L);
Position First(List L);
Position Advance(Position P);
ElementType Retrieve(Position P);