Clostridium perfringens
Some weakly beta-hemolytic species cause intense beta hemolysis when grown together with a strain of "Staphylococcus". This is called the "CAMP test". "Streptococcus agalactiae" displays this property. "Clostridium perfringens" can be identified presumptively with this test. "Listeria monocytogenes" is also positive on sheep's blood agar.