I deserialize a json string that was created by the serialize method. The JSON (from the Newtonsoft library) looks like this (a little bit formatted for better reading):

{"AreaKindList":
[
    {"ID":1,"Kind":"Lioncage"},
    {"ID":2,"Kind":"Open-Air Enclosure"}
],
"AnimalRaceList":
[
    {"ID":1,"Race":"Lion","AllowedAreaKinds":[1]},
    {"ID":2,"Race":"Gazelle","AllowedAreaKinds":[2]},
    {"ID":3,"Race":"Antelope","AllowedAreaKinds":[2]}
],
"AreaList":
[
    {"ID":1,"AreaKindId":1,"Size":2,"AnimalList":
                                    [
                                        {"Name":"Leo","RaceId":1}
                                    ]
    }
]}

And the classes look like this:

public class Zoo
{
    public List<AreaKind> AreaKindList { get; set; }
    public List<AnimalRace> AnimalRaceList { get; set; }
    public List<Area> AreaList { get; set; }
}

public class AreaKind
{
    public int ID { get; private set; }
    public string Kind { get; private set; }
    public AreaKind(int id, string kind)
    {
        ID = id;
        Kind = kind;
    }
}

public class AnimalRace
{
    public int ID { get; private set; }
    public string Race { get; private set; }
    public List<int> AllowedAreaKinds { get; private set; }
    public AnimalRace (int id, string race, List<int> areaKindIds)
    {
        ID = id;
        Race = race;
        AllowedAreaKinds = areaKindIds;
    }
}

public class Area
{
    public int ID { get; private set; }
    public int AreaKindId { get; set; }
    public int Size { get; set; }
    public List<Animal> AnimalList { get; set; }
    public Area(int size, int areaKindId, int id)
    {
        ID = id;
        AreaKindId = areaKindId;
        Size = size;
    }
}

As you can see there is a list of numbers inside the AnimalRaceList, named AllowedAreaKinds. At this moment there is only 1 entry inside. When I use the following code to deserialize the zoo-object the zoo is completly filled (including the animal Leo with the ID of 1), but the "List AllowedAreaKinds" is completly set to "NULL". Why?

using (StreamReader reader = File.OpenText(Program.JsonFile))
{
    JsonSerializer serializer = new JsonSerializer();
    Zoo tempZoo = (Zoo) serializer.Deserialize(reader, typeof(Zoo));
}

I even changed the serializer against a Populate(), but that gave the same result. Anyone an idea what it could be?