We may also， I think， see in the peculiar organization of the entire family of the Megapodidae or Brush Turkeys， a reason why they depart so widely from the usual habits of the Class of birds. Each egg being so large as entirely to fill up the abdominal cavity and with difficulty pass the walls of the pelvis， a considerable interval is required before the successive eggs can be matured (the natives say about thirteen days). Each bird lays six or eight eggs or even more each season， so that between the first and last there may be an interval of two or three months. Now， if these eggs were hatched in the ordinary way， either the parents must keep sitting continually for this long period， or if they only began to sit after the last egg was deposited， the first would be exposed to injury by the climate， or to destruction by the large lizards， snakes， or other animals which abound in the district； because such large birds must roam about a good deal in search of food. Here then we seem to have a case in which the habits of a bird may be directly traced to its exceptional organization； for it will hardly be maintained that this abnormal structure and peculiar food were given to the Megapodidae in order that they might not exhibit that parental affection， or possess those domestic instincts so general in the Class of birds， and which so much excite our admiration.
It has generally been the custom of writers on Natural History to take the habits and instincts of animals as fixed points， and to consider their structure and organization， as specially adapted， to be in accordance with these. This assumption is however an arbitrary one， and has the bad effect of stifling inquiry into the nature and causes of "instincts and habits，" treating them as directly due to a "first cause，" and therefore， incomprehensible to us. I believe that a careful consideration of the structure of a species， and of the peculiar physical and organic conditions by which it is surrounded， or has been surrounded in past ages， will often， as in this case， throw much light on the origin of its habits and instincts. These again， combined with changes in external conditions， react upon structure， and by means of "variation" and "natural selection"， both are kept in harmony.
My friends remained three days， and got plenty of wild pigs and two Anoas， but the latter were much injured by the dogs， and Icould only preserve the heads. A grand hunt which we attempted on the third day failed， owing to bad management in driving in the game， and we waited for five hours perched on platforms in trees without getting a shot， although we had been assured that pigs， Babirusas， and Anóas would rush past us in dozens. I myself， with two men， stayed three days longer to get more specimens of the Maleos， and succeeded in preserving twenty-six very fine ones--the flesh and eggs of which supplied us with abundance of good food.