Lower Jaw of _Neoceratodus forsteri_. 616 Adult Male of _Lepidosiren paradoxa_. 619 _Lepidosiren paradoxa._ Embryo Three Days before Hatching; Larva Thirteen Days after Hatching. 620 Larva of _Lepidosiren paradoxa_ Forty Days after Hatching. 621 Larva of _Lepidosiren paradoxa_ Thirty Days after Hatching. 621 Larva of _Lepidosiren paradoxa_ Three Months after Hatching. 621 _Protopterus dolloi._ 622 [Illustration: FIG. 1.--Long-eared Sunfish, _Lepomis megalotis_ (Rafinesque). (From life by R. W. Shufeldt.)--Page 2.] CHAPTER I THE LIFE OF THE FISH A POPULAR ACCOUNT OF THE LIFE OF THE LONG-EARED SUNFISH, _LEPOMIS MEGALOTIS_ =What is a Fish?=--A fish is a back-boned animal which lives in the water and cannot ever live very long anywhere else. Its ancestors have always dwelt in water, and most likely its descendents will forever follow their example. So, as the water is a region very different from the fields or the woods, a fish in form and structure must be quite unlike all the beasts and birds that walk or creep or fly above ground, breathing air and being fitted to live in it. There are a great many kinds of animals called fishes, but in this all of them agree: all have some sort of a back-bone, all of them breathe their life long by means of gills, and none have fingers or toes with which to creep about on land.