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Detailed measurements of the magnetic and transport behavior of the two single crystals exhibiting colossal magnetoresistance are summarized. The sample exhibits unusual exponents (, , , ) and, more importantly, a Griffiths phase characterized by an exponent . By contrast, the specimen displays Heisenberg model behavior with no evidence of such a phase. Thus while a Griffiths phase accounts for the behavior of near optimal doping, it does not appear to be a prerequisite for colossal magnetoresistance in this system.