"As things stand today, Homo Sapiens, our own species, is unique in being the only member of a genus - the genus Homo has but a single member. Linnaeus saw things differently, however, and should not be accused of displacing Homo Sapiens too far from the other animals - he included several other species of 'man' in the genus Homo, based on folk legends and myths of tailed men, 'troglodytes' and so on. He also agonized about whether there ought to be a separate genus for Homo at all. In the foreword to his Fauna Svecica, published in 1746, he said 'the fact is that as a natural historian I have yet to find any characteristics which enable man to be distinguished on scientific principles from an ape', and in response to criticism of this position he wrote to a colleague, Johann Gmelin, in 1747:

I ask you and the whole world for a generic differentia between man and ape which conforms to the principles of natural history. I certainly know of none... If I were to call man ape or vice versa, I should bring down all the theologians on my head. But perhaps I should still do it according to the rules of science.

In other words, it was Linnaeus's own belief that man belonged in the same genus as the apes, a belief thoroughly born out by modern studies of the similarities between the DNA of humans, chimpanzees and gorillas. if the classification were being made from scratch today, using the DNA evidence, man would actually be classified as a chimpanzee - Pan Sapiens, perhaps. It is only through a historical accident and Linnaeus's fear of arousing the wrath of the theologians that Homo sapiens sits in unique and isolated splendour as the sole member of a genus."

p218-19 John Gribbin, Science: A History

Linnaeus links:

The Father of Taxonomy
Order from Chaos
The Linnean Society
Linnaean Correspondence
wikipedia entry