Birds , fish , and amphibians are " oviparous "

鸟类、鱼和栖类是“卵生”的动物

Primitive oviparous mammals found only in australia tasmania and new guinea .

只在澳大利亚塔斯马尼亚岛和新几内亚发现的原始卵生哺乳动物。

Worms and insects : oviparous , viviparous , aquatic .

虫:卵生、化生、湿生。

In 1843 , friedrich engels saw an egg of a duckbill in england . People told him that it was a mammal animal from australia . He broke into laughter after hearing it and said : " all the mammal animals were viviparous . The duckbill was oviparous , so it could not be a mammal animal " .

1843年恩格斯在英国看到一只鸭嘴兽的蛋，人们告诉他，这是澳大利亚的一种哺乳动物，恩格斯听后哈哈大笑说：“哺乳动物都是胎生的，鸭嘴兽是卵生的，因此肯定不是哺乳动物。”