The Freshwater Jelly-fish of Lake Tanganyika (_Limnocnida Tanganyicae_), magnified five times linear. Since its discovery in Tanganyika it has been found also in the Lake Victoria Nyanza and in pools in the Upper Niger basin.] [Illustration: FIG. 17. The Giraffe-like animal called the Okapi, discovered by Sir Harry Johnston in the Congo Forest. Photograph of the skin of a female sent home by him in 1901, and now mounted and exhibited in the Natural History Museum.] [Illustration: FIG. 18. Two “bandoliers” cut by the natives from the striped part of the skin (the haunches) and at first supposed to be bits of the hide of a new kind of Zebra. These were sent home by Sir Harry Johnston in 1900.] The main result of a good deal of such investigation is measured by our increased knowledge of the pedigree of organisms, what used to be called ‘classification.’ The anatomical study by the Australian professors, Hill and Wilson, of the teeth and the fœtus of the Australian group of pouched mammals--the marsupials--has entirely upset previous notions, to the effect that these are a primitive group, and has shown that their possession of only one replacing tooth is a retention of one out of many such teeth (the germs of which are present), as in placental mammals; and further that many of these marsupials have the nourishing outgrowth of the fœtus called the placenta fairly well developed, so that they must be regarded as a degenerate side-branch of the placental mammals, and not as primitive forerunners of that dominant series. [Illustration: FIG. 19. Photograph of the skull of a male Okapi--showing the paired boney horn-cores--similar to those of the Giraffe, but connected with the frontal bones and not with the parietals as the horn-cores of Giraffes are.] [Illustration: FIG. 20. Drawings by Professor Grassi, of Rome, of the young of the common Eel and its metamorphosis. All of the natural size. The uppermost figure represents a transparent glass-like creature--which was known as a rare “find” to marine naturalists, and received the name _Leptocephalus_. Really it lives in vast numbers in great depths of the sea--five hundred fathoms and more. It is hatched here from the eggs of the common Eel which descends from the ponds, lakes, and rivers of Europe in order to breed in these great depths. The gradual change of the _Leptocephalus_ into a young Eel or “Elver” is shown, and was discovered by Grassi. The young Eels leave the great depth of the ocean and ascend the rivers in immense shoals of many hundred thousand individuals, and wriggle their way up banks and rocks into the small streams and pools of the continent. The above figures were published by Professor Grassi in November 1896, in the _Quarterly Journal of Microscopical Science_, edited by E. Ray Lankester and published by Churchill & Sons.]