Abstract: The Latin names of taxa above the rank of genus always have to be transformed into English. This transfozmation is very simple, only the endings of the Latin names need to be changed. In usage there is a subtle difference between Latin names and their English equivalents. 1 .The Latin names of taxa are mainly used in classification and nomenclature. They are always written with a capital initial letter. But the English equivalents are usually written with a small initial letter, unless they appear at the beginning of a sentence. 2. The Latin names of taxa are used far from frequent as their English equivalents. In some situations, it is not appropriate to use Latin names, especially when we describe the characters and ecological features as well as geological ranges etc. in these cases, the English names are preferable, such as follows. "As in many primitive ornithopods" (don`t use "Ornithopoda"); "The skulls of hadrosaurs" (not prefer "Hadrosauridae"); "Thecodonts (not prefer "Thecodontia")appeared at the end of the Permian and diversiffied throughout the Triassic Period". "The earliest fossil cyprinids" (not prefer "Cyprinidae") "The oldest known diapsid" (not prefer "Diapsida"). 3. The generic names are used as singular common nouns as English words, but they are always written with a capital initial letter and printed in italic type.