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yet liere we find an exception utterly unexpected and incom- 

 prehensible. In the large families of the grasses, sedges, and 

 rushes, the carpels are generally two, and those so well developed 

 and so regular in their size as not to admit of the supposition of a 

 suppression of parts, while on the other hand ovaries of three 

 carpels are often found among the Dicotyledonous plants combined 

 with flowers whose other parts do not follow the same arrangement. 

 Besides this striking occurrence of Number Three we find 

 instances of it in unexpected places, as m the presence of trifid 

 hairs or trichotomous cymes, and doubtless each instance is re- 

 plete with instruction could we but trace it. In the Animal 

 Kingdom three is not a common number, and when met with is 

 always associated with something strange or exceptional. Such 

 an instance is the easel-like form of many Crustaceans in their 

 first stage, which is remarkable not only from its utter dissimi- 

 larity to any form of the animal, but also from its trenching, as it 

 were, on the province of mechanics, presenting us with that form 

 of structure, a hollow pyramid, which has always beon held the 

 most stable of all, in a swimming animal, who has no need of sta- 

 bility. Again, many of our insects have three eyes, or ocelli, 

 placed in the form of a triangle, on their foreheads. We can 

 scarcely realise the necessity for these organs, the insects who 

 bear them being provided with compound eyes constructed to 

 cover the whole field of possible vision. If we suppose, as has 

 been suggested, that the so-called compound eyes are not actually 

 organs of sight, we are left in the hopeless difiiculty of assigning 

 another use for them. If we look upon the ocelli as merely a 

 ■ reduced copy of the Arachnid type, our perplexities increase. The 

 .spider's eyes, whether two, six, or eight, are arranged in pairs, and 

 the suppression of single eyes could not possibly make an equi- 

 lateral triangle. The ocelli remain a unique and unmistakeable 

 distinction of the insect tribe. In the Mineral Kingdom we find 

 occasional trihedral prisms and pyramids, but we rather associate 

 the Number Three with the axes by reference to which crystalline 

 forms are classified. Artificial as this arrangement may seem, it 



