A New Hampshire man who police said beat and burned his girlfriend’s 3-year-old son last month before fleeing and being captured with her at a Florida theme park has pleaded not guilty to felony charges. Bail remains at $500,000 for Roland Dow, 27, of Plaistow. Dow is charged with several counts of assault and child endangerment in the burning and beating of James Linscott. Dow pleaded not guilty Monday in Rockingham Superior Court. Police said Dow struck the boy in the head so hard he caused traumatic brain injury and seizures. The boy’s mother, Jessica Linscott, 23, is charged with multiple counts of child endangerment in failing to get medical treatment sooner.