Sinatra failing to produce multiple param values

sinatra-multiple-values-fail

Sinatra 1.2.6 doesn't appear to properly handle multiple values for a form parameter. 'params[:my_param_name]'
only returns the last one supplied. I've verified that Chrome is sending the full list, and the list appears in 
the rack.request.query_string variable (but not the rack.request.params variable).

get '/lame' do
  erb :lame
end

post '/lame' do
  puts params.inspect
  puts request.inspect
  puts params[:select_multiple_values]
end

# or use curl -X POST 'http://localhost:8000/lame/?select_multiple_values=oink&select_multiple_values=foo&select_multiple_values=bar'

<!-- lame.erb -->
<form method="POST" action="/lame">
<select name="select_multiple_values" multiple size="5">
  <option value="First Option">Option 1
  <option value="Second Option">Option 2
  <option value="Third Option">Option 3
</select>
<input type="submit">
</form>