diff --git a/api.specification b/api.specification
index e7117ed89..1120620e9 100644
--- a/api.specification
+++ b/api.specification
@@ -126,6 +126,10 @@ The following sections briefly describe the contents of the different types.
  * The base type
  * The clause, which is a type parameter section, described previously
 
+=== Polymorphic ===
+ * The base type
+ * The type parameter section, described previously
+
 = API Data Structure =
 
 This section and explains the data structure representing the API of a source file described in the previous section.
@@ -187,7 +191,7 @@ Type
 		EmptyType
 		Parameterized
 			baseType : SimpleType
-			typeArguments: SimpleType*
+			typeArguments: Type*
 	Annotated
 		baseType : SimpleType
 		annotations : Annotation*
@@ -198,6 +202,9 @@ Type
 	Existential
 		baseType : Type
 		clause: TypeParameter*
+	Polymorphic
+		baseType : Type
+		clause: TypeParameter*
 }}}
 
 There is one point to note about the access hierarchy.  It includes a Pkg class, which represents Java's package private access.  This is only used for Java sources.
diff --git a/interface/definition b/interface/definition
index 2365e9ee5..a89b238b9 100644
--- a/interface/definition
+++ b/interface/definition
@@ -42,7 +42,7 @@ Type
 		EmptyType
 		Parameterized
 			baseType : SimpleType
-			typeArguments: SimpleType*
+			typeArguments: Type*
 	Annotated
 		baseType : SimpleType
 		annotations : Annotation*
@@ -53,6 +53,9 @@ Type
 	Existential
 		baseType : Type
 		clause: TypeParameter*
+	Polymorphic
+		baseType: Type
+		parameters: TypeParameter*
 
 Access
 	Public