The whole island teems with animal life in great variety of forms. It would appear, judging from the success of Mr. A. R. Wallace, to be a paradise for the entomologist. This gentleman once collected seventy-six species of beetles in one day, many of which were new and of remarkable form, and during his stay of fifteen months in Sarawak he took over 500 species. There are a number of handsome species of butterflies, including the magnificent _Ornithoptera Brookana_. This butterfly is eight inches in width, and of a rich, velvety black color, on which is a broad band of metallic green scales, resembling a humming-bird’s feathers. Of all insects Borneo is richest in moths. At one place, on a mountain top, Mr. Wallace took 200 specimens in a single night, representing 130 species. In the same place he took in twenty-six nights 1,300 specimens of moths. The fishes include quite a variety of fresh-water species, among which may be mentioned the curious tree-climbing perch, the thread-fish, the celebrated _gourami_, the jumping-fish, or _Periophthalmus_, which hops about on land in search of small crustaceans stranded by the receding tide; and the very rare and curious little fish known to icthyologists as _Luciocephalus pulcher_. The Malays capture a great many fish in small streams by poisoning the water with an extract made from the pounded roots of the tuba plant, and either spearing or netting the fish when they rise to the surface to breathe. Among the reptiles, the most important is the crocodile, which attains a maximum length of seventeen feet, and is very destructive to human life. It seldom happens that a person escapes or is rescued, after being seized in this burly reptile’s powerful jaws. Some years ago the Sarawak government began a war of extermination against the crocodiles, by offering a reward of 35 cents a foot for all killed in the Territory. In 1878, 266 crocodiles were killed, and $738 paid out in rewards. I discovered a crocodile’s nest containing fifty-five eggs. The native crocodile hunters use hook and line. The hook, or _alir_, as it is called by the Malays, is a simple contrivance made of wood, tied at the end of a tough bark rope. Another saurian, the gavial, is found in Borneo. It is not unlike that of the Ganges, called by Dr. Gray, _Tomistoma schlegelli_. This species inhabits the headwaters of some of the rivers, and is rarely seen. In the swampy forest near the coast, small reptiles are very abundant. There are pythons in Borneo twenty-four feet long. Two twelve-foot specimens were brought to me, and a monster python twenty feet six inches long, I purchased alive in a cage, and put to death for its skin and skeleton.