. Science from an easy chair; a second series. Science; Natural history. STRUCTURE OF SEA-SQUIRT'S TADPOLE 287 important structures in which the Ascidian tadpole and the frog's tadpole agree—structures which are possessed by all vertebrates and by no other animals. And not only do thtse structures, as shown in the Ascidian tad- pole, agree in their shape and relations to other parts with the similar structures of vertebrates, but actually in their mode of building up, cell by cell, from the primitive egg-cell, the structures compared are demonstrated by careful microscopic study to be identica
. Science from an easy chair; a second series. Science; Natural history. STRUCTURE OF SEA-SQUIRT'S TADPOLE 287 important structures in which the Ascidian tadpole and the frog's tadpole agree—structures which are possessed by all vertebrates and by no other animals. And not only do thtse structures, as shown in the Ascidian tad- pole, agree in their shape and relations to other parts with the similar structures of vertebrates, but actually in their mode of building up, cell by cell, from the primitive egg-cell, the structures compared are demonstrated by careful microscopic study to be identical. What, then, must we conclude ? This is a case of cumulative evidence. If one met—say, near the North Pole—a race of men with. Fig. 36.—A drawing of the head of an Ascidian tadpole seen as a transparent object under the microscope. C marlcs the tail, only partly shown; K is the gullet; N is the nervous system tapering to form the spinal cord n behind and expanding in front to form the hollow brain N'. On the inner wall of this we see O the eye and a an auditory organ; o is the aperture of the mouth j ch the notochord (unshaded); d the intestine; « is one of a pair of ad- hesive outgrowths by which the tadpole fixes itself permanently to a piece of rock. the colour and appearance of New Zealanders, one would say, " It is very curious ! They are like New ; But if one found that they could speak the Maori language and no other, it would be rendered nearly certain that they were New Zealanders. If after this you found that they decorated themselves with the tattoo-markings of New Zealanders, and then that they possessed weapons and carvings of the Maori pattern, your conclusion would be. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Lankester, E. Ray (Edwin Ray), Sir, 1847-1929.
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