(a) Amelus ( = a limb), or absence of all the extremities. The body is usually well formed, but at the shoulders and hips there are short rounded or warty projections, at the ends of which there may be horny or nail-like appendages. Sometimes there are ill-formed bones present.

(b) Peromelus ( = maimed). The whole four extremities are defective or deformed (Fig. 13). The body may be well formed, but sometimes the deformity is associated with other malformations which prevent the persistence of life.

(c) Phocomelus ( =a seal). This is a variety of the former, in which the long bones are absent or very defective, and the hands and feet are seated immediately on the shoulders and hips and are well formed.