We have explained in our article Biblical Formatting located on the world wide web at http://www.Rashiyomi.com/biblicalformatting.pdf, that the Biblical Author indicates bold, italics, underline by using repetition. In other words if a modern author wanted to emphasize a word they would either underline, bold or italicize it. However when the Biblical author wishes to emphasize a word He repeats it. The effect - whether thru repetition or using underline - is the same. It is only the means of conveying this emphasis that is different.

Note the emphasized underlined word water in the following verses, Lv11-09:12 discussing the kashruth of fish: These shall you eat of all that are in the waters; whatever has fins and scales in the waters, in the seas, and in the rivers, those shall you eat. ...And all that have not fins and scales in the seas, .... they shall be an abomination to you; .... What ever has no fins nor scales in the waters, that shall be an abomination to you. The repeated underlined word waters creates an unspecified emphasis similar to the emphasis indicated by a modern author by use of underlines. Hence the Rashi comment: If the fish never had any fins/scales it is not kosher; but if it had fins/scales at least in the water (but lost them when captured on dry land) then they are kosher. As usual, the point Rashi is making may seem obvious until we articulate it using Talmudic analytic methods: The driving force of permission is not the actual fins/scales but rather the fact that this species of fish is known for fins/scales. The actual fins and scales do not have to be present.