Sentence:  The Kamilaroi are divided into six gentes, standing with reference to the right of marriage, in two divisions, ... Originally the first three gentes were not allowed to intermarry with each other, because they were subdivisions of an original <WSD>gens</WSD>; but they were permitted to marry into either of the other gentes, and "vice versâ". 
Meaning of the word marked with <WSD> tags:  A tribal subgroup whose members are characterized by having the same descent, usually along the male line.