pillar and waves era spanish cob type coin - with its # tic tac toe design -- 78 P -- on the bottom row means --1678 -Potosi mint

-- the top middle row number is its "value"
coins were often hole for 2 reasons --(1) by making a hole in the coin and by keeping the small amount of silver from doing it -- the hole maker screwed the next guy out of a small bit of silver ( which the hole maker then saved up and when he had enough , he melted it into into a silver blob and sold it ) -- shaving the edges of the silver coins was also quite common as well -- so much so that many vendors had scales and weighted a coin before accepting it in payment --- and (2) they
strung them on a string to safeguard them from loss , yet keep em handy for use. --especially true of smaller coins which were used a lot for everyday use.