1 THE ANIMAL KINGDOM. 



There are also four forms of Papilio ajax, tlie three others being originally 

 described as distinct species under the name of P. 3Iarcellus, P. ielamonides, and P. 

 walshii. Our Papilio c/laucus is now known to be a dark, dimorphic, climatic form of 

 the common Papilio turmts. There are dimorphic males among certain beetles, as in 

 the Golofa hastata of Mexico, in which one set of males are large and have a very 

 large erect horn on the prothorax, and in the other the body is much smaller, with a 

 very short conical horn. 



Temperature is also associated witli the production of ijolymorjjhic forms in the 

 temperate regions of the earth, as seen in certain butterflies, southern forms being 

 varieties of northern forms, and alpine ' species ' proving to be varieties or seasonal 

 forms of lowland species. For example, Weismann states that the European butter- 

 flies, Lycaon amyntas and polysperchon are respectively summer and spring broods. 

 Anthocharis simploiiica is an Alpine winter form of Anthocharis delia, as is Pieris 

 hryonice of Pieris 7iapi. lu this country, as Edwards has shown, two of the polj-- 

 morphic forms of Papilio ajax — i. e., icalshii and telamonides — come from winter 

 chrysalids, and P. Marcellus from a second brood of summer chrysalids. It thus 

 appears that polymorphism is intimately connected with the origin of sjDecies. Per- 

 haps the most remarkable case of polymori)hism is to be seen in the white ants {Ter- 

 mites), W'here in one genus there are two sorts of workers, two sorts of soldiers, and 

 two kinds of males and fem.ales, making eight sorts of individuals ; in the other genera 

 there are six. Among true ants there are, l^esidcs the ordinary males, females, and 

 workers, large-headed workers. In the honey-ant {Myrmecocystus mexicatius), be- 

 sides the usual workers, there are those with enormous abdomens filled with honey. 

 Other insects, especially certain grasshoppers, are dimorphic. Certain parasitic nema- 

 tode worms are dimor])hic ; and among the ccElenterates, especially the hydroids, there 

 is a strong tendency to |iolymorphism. 



EVOLUTION. 



In a single word — evolution — is comprised that vast complex of factors which 

 has resulted in the stocking of our earth with plants and animals, each after its kind. 

 The explanation of the process by which the life-forms of this planet have been 

 brought into existence is an intricate series of problems within problems, as infinite as 

 is the variety in nature itself. In early pre-scientific times, in the childhood of the race, 

 it seemed sufficient to say that every living thing was created, and with this statement 

 the m.ajority of mankind were content to rest ; not so, however, a few isolated 

 thinkers, who, from the time of Democritus, have questioned nature, and as earnestly 

 as reverently sought how these things could have come to pass. When geology began 

 to assume a definite shape; when Cuvier and Lamarck had sketched out the leading 

 types of animal life, as Jussieu did the earth's flora ; and after palaeontology began to 

 be a science, and it became known that the earth had been peopled by successive floras 

 and faunas, appeared Lamarck and St. Hilaire as philosophers, who combated the 

 cataclysmic ideas of Cuvier, and who maintained both the unity of organization of 

 organic beings and the immense lapse of time since the beginning of life — time 

 enough for the changes and adaptations needed to bring about the present condition of 

 things. In 1802, twenty-three years before the appearance of Cuvier's Discourse 

 Sur les Revolutions du Globe, Lamarck uttered these striking words ; '■'■Pour la nature, 

 Ic temps ri'est rien, et ti' est jamais une diffictdte ; elle fa toujours d, sa disposition, et 



