========================+========+========+========+========+======== | FISH | TADPOLE| FROG | TURTLE | LIZARD ------------------------+--------+--------+--------+--------+-------- | | | | | Limbs, kind and number | | | | | | | | | | ------------------------+--------+--------+--------+--------+-------- | | | | | Are claws present? How | | | | | many? | | | | | | | | | | ------------------------+--------+--------+--------+--------+-------- | | | | | Covering of body | | | | | | | | | | ------------------------+--------+--------+--------+--------+-------- | | | | | Teeth, kind of, if | | | | | present | | | | | | | | | | ------------------------+--------+--------+--------+--------+-------- | | | | | Which bones found in man| | | | | are lacking? | | | | | | | | | | ------------------------+--------+--------+--------+--------+-------- | | | | | Chambers of heart | | | | | | | | | | ------------------------+--------+--------+--------+--------+-------- | | | | | Respiration | | | | | | | | | | ------------------------+--------+--------+--------+--------+-------- | | | | | Movements | | | | | | | | | | ========================+========+========+========+========+======== [Illustration: FIG. 283.--BIG-HEADED TURTLE (_Platysternum megalocephalum_). × ¹⁄₂. China. This and Fig. 282 suggest descent of turtles from a lizardlike form. Figure 282 shows earlier ancestors to have been gill breathers.] CHAPTER XIII BIRDS [Illustration]