Finally, it is worth noting that this covering, or half covering, is only one of the means by which savage men and women endeavor to direct attention to that which civilized man conceals from a sense of shame. Among the Admiralty Islanders, the only covering is a shell, which shell is often tastefully engraved with the usual zigzag patterns, whilst its dazzling whiteness forms a very striking contrast with the blackness of the skin.[1217] On reaching puberty, the Tankhul Nagas assume, instead of a shell, a horn or ivory ring from an eighth to a quarter of an inch in breadth; being apparently of opinion that exposure, if so attended, is not a matter to be ashamed of.[1218] Some of the Brazilian Tupis, according to Castlenau, “mentulam inserunt in annulum ligneum, unde appellantur Porrudos, _i.e._ mentulati;”[1219] and, in several of the South Sea Islands, those parts of the body which civilized people are most anxious to conceal, are decorated with tattoos.[1220] De indigenis Tanembaris et Timorlaonis dum loquitur Reidel, adulescentes et puellas dicit saepe consulto abradere pilos pubis nulla alia mente, nisi ut illæ partes alteri sexui magis conspicuæ fiant.[1221] Above all the practice of circumcision should be noticed in this connection, since, as I believe, it owes its origin to the same cause. It is by no means a specifically Jewish custom, but is widely spread over the earth. It is in use among all the Mohammedan peoples, among most of the tribes inhabiting the African West Coast, among the Kafirs, among nearly all the peoples of Eastern Africa, among the Christian Abyssinians, Bogos, and Copts,[1222] throughout all the various tribes inhabiting Madagascar,[1223] and, in the heart of the Black Continent, among the Monbuttu and Akka. Moreover, it is practised very commonly in Australia, in many islands of Melanesia,[1224] and in Polynesia universally. It has also been met with in some parts of America: in Yucatan,[1225] on the Orinoco,[1226] and among certain tribes in the Rio Branco in Brazil.[1227] The Jews, Mohammedans,[1228] Abyssinians,[1229] and some other peoples being excepted, it is always performed when the boy attains manhood—_i.e._, at the same age as that at which he is tattooed or painted, or begins to dress or adorn himself. Indeed, through the operation of circumcision, the boy becomes a man, and, where it is wanting, some other operation or deformation of the body supplies its place.[1230] Thus, in Australia, some tribes practise circumcision, others knock out teeth, when the youth becomes virile.[1231] Where circumcision is in use it is generally considered an indispensable preliminary to marriage, “uncircumcised” being a bad word, and the women often refusing all intercourse with such a man.[1232]