I can't supply an exact rendering without additional context, but 'intertenent' means 'they hold (or own) jointly (lit., 'hold between themselves', i.e., in respect of property and the like), and 'quateria' seems to be an ablative of degree of difference.

The phrase would thus mean something like, 'They hold a fourth part jointly' in English (i.e., 'They jointly own a fourth of x').