2. Connecting links can be found among organisms that are still living.
3. Eg. :(a) ‘Peripatus’ has segmental nephridia, thin cuticle and parapodia - like appendages as in Annelida. At the same time it has trachea and open circulation as in Arthropoda.
(b) The duck-billed platypus lays eggs like reptiles and has hair and mammary glands like mammals.
(c) Lung fish, though a fish, breathes air through its lungs.
4. These organisms point strongly to the fact that mammals have evolved from reptiles and amphibia from fishes.