!4!!1--1
!21--1. Standard Common Lisp types. All these types except atom and common have\penalty -\@M a corresponding class.!!1--5
!21--2. This figure shows all required subclass relationships among the classes that\penalty -\@M are instances of standard-type-class, with the exception of classes defined by means of\penalty -\@M defstruct. Implementations may choose to impose additional ones.!!1--7