is examined by comparing optical designs of the eyes of present day animals and comparing the advantages and disadvantages of each design. One can extrapolate from the eye designs of today that these eyes may have benefited the animals to be able to adapt to their environment. It is interesting to note that of the myriad of species that have evolved, there are several different eye designs, instead of one or two successfully dominant designs. One argument for such a diversity of eyes is that one kind of eye would not easily evolve into ano ....