In regard to the motive of jealousy as connected with the question of progeny--the care to be sure of a man's own real paternity of his children, we may remark that this motive must be absent in many tribes, viz. in those tribes where the physiological rôle of the father in procreation is not known. We know with all certainty that this is the case in the Central and North Central tribes, as well as in the North-east part of the continent.[349] But it appears to be the case in the South Central tribes. It is stated that the Urabunna have quite analogous beliefs in reincarnation of ancestors, in their dwelling-places, and other totemic matters.[350] Spencer and Gillen do not say anything definite about the appreciation or want of knowledge of physiological paternity, but that is perhaps because they were less well acquainted with the Urabunna, who were also probably in a more advanced stage of decay. By analogy it may be inferred that the Urabunna, like all the other neighbouring tribes, had with the whole apparatus of analogous beliefs, also the lack of the knowledge in question. We might infer the same about the Dieri and kindred tribes, who seem to be almost identical in all respects with the Urabunna, but of whose religious and totemic ideas we are by no means so well informed as of their social organization; in fact, for these psychological data it is undoubtedly to Spencer and Gillen that we owe the major part of our knowledge about Australia. [349] See below, pp. 209 _sqq._ and 226. [350] Spencer and Gillen, _Nor. Tr._, pp. 146 _sqq._ Certainly the ignorance of physiological fatherhood in the South Central tribes is of a hypothetical character. But provided it is a fact, we see that the area occupied by tribes which believe in the supernatural begetting of children extends over the whole Central and North-east area. There is no evidence on this point in the case of the Western tribes. We find only in the South-eastern tribes a knowledge of the real process of procreation. It is interesting to note that thus the area of greater sexual promiscuity and less pronounced jealousy is conterminous with the area where natural paternity is unknown. Whether there be any real dependence between these two series of facts it is impossible to assert, as our knowledge of the natives' psychology is too scanty. But if our information on this point be reliable, and if these limits be correct, then the coincidence just noted is rather suggestive.