I always kind of wondered, without inquiring actively into the subject, why cat breeds don't show as much variety as dog breeds even though cats have been domesticated for almost as long. A comment thread at a biologist's anniversary weblog of The Origin of Species suggests the answer: until recently—i.e., after Darwin's own time—breeding cats was considered too difficult to be worth the trouble. The big man writes in his chapter on artificial selection that
cats, from their nocturnal rambling habits, cannot be matched, and, although so much valued by women and children, we hardly ever see a distinct breed kept up; such breeds as we do sometimes see are almost always imported from some other country, often from islands.
Perhaps Darwin was familiar with the curiously tailless cats from the Isle of Man. Come to think of it, they're good little refuters of Lamarckism, since only Manx cats give birth to other Manx cats, and you can't make more by sawing their tails off.