<prompt> All are motile, EXCEPT:Cl.histolyticumCl.tetanosporumCl.perfringensCl.septicum  <response>: C perfringens is a large, Gram-positive, nonmotile rod with square ends. Hemolysis and gas production are characteristic. In broth containing fermentable carbohydrate, growth of C perfringens is accompanied by the production of large amounts of hydrogen and carbon dioxide gas, which can also be produced in necrotic tissues; hence the term gas gangrene. Ref: Ray C.G., Ryan K.J. 2010. Chapter 29. Clostridium, Peptostreptococcus, Bacteroides, and Other Anaerobes. In C.G. Ray, K.J. Ryan Eds, Sherris Medical Microbiology, 5e. 