Accessing Iteration Dates through REST API

How should I go about getting the start and end dates for an iteration through the API?

If I attempt to access the iteration directly (using the URL retrieved by /_apis/wit/classificationnodes/iterations/{parent}&$depth=2) I receive a 'Node ID is not recognized' error:

{"$id": "1","innerException": null,"message": "TF51541: The Node ID is not recognized.","typeName": "Microsoft.TeamFoundation.WorkItemTracking.Server.Metadata.WorkItemTrackingTreeNodeNotFoundException, Microsoft.TeamFoundation.WorkItemTracking.Server, Version=14.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a","typeKey": "WorkItemTrackingTreeNodeNotFoundException","errorCode": 0,"eventId": 3200
}