diff --git a/src/Observable.ts b/src/Observable.ts
index 0fbce813a2..c7dcd0e17f 100644
--- a/src/Observable.ts
+++ b/src/Observable.ts
@@ -28,7 +28,7 @@ export default class Observable<T>  {
    * @param {Function} subscribe the function that is
    * called when the Observable is initially subscribed to. This function is given a Subscriber, to which new values
    * can be `next`ed, or an `error` method can be called to raise an error, or `complete` can be called to notify
-   * of a succesful completion.
+   * of a successful completion.
    */
   constructor(subscribe?: <R>(subscriber: Subscriber<R>) => Subscription<T>|Function|void) {
     if (subscribe) {
@@ -52,7 +52,7 @@ export default class Observable<T>  {
   
   /**
    * @method lift
-   * @param {Operator} the operator defining the operation to take on the observable
+   * @param {Operator} operator the operator defining the operation to take on the observable
    * @returns {Observable} a new observable with the Operator applied
    * @description creates a new Observable, with this Observable as the source, and the passed 
    * operator defined as the new observable's operator.
@@ -109,6 +109,7 @@ export default class Observable<T>  {
   /**
    * @method forEach
    * @param {Function} next a handler for each value emitted by the observable
+   * @param {PromiseConstructor} PromiseCtor? a constructor function used to instantiate the Promise
    * @returns {Promise} a promise that either resolves on observable completion or
    *  rejects with the handled error
    */