These 0 kb fonts are all old Mac format fonts and are not usable on Windows.
If a file is beginning with a dot in its name it is under default settings invisible.
The Mac will write to every file on any drive a second file with the very same name but a ._ before. This file does only store how the file is presented (looks like) in the finder. Ignore those files. Go down in you list and take the original files as we can even see them in your screen shot. You can delete the other files here with the dot before without doing any damage.
Don't change the file's extension, it could cause damage.
Myriad Pro is available in the TypeKit.
@ Peter: These are not old files, they are created in the moment when you look at the folder the first time in the Finder.
Willi, the filenames that start with the dot in the screenshot are the resource forks for the Mac format fonts. I didn't say the files were old, only the that the fonts are old Mac format.
Mac normally hides the resource fork from you, where Windows will display it, but it is not usable by any Windows OS, and in Mac format fonts that's where the actual font data is stored.
No, the font data is stored only in the OTF or TTF or DFONT files, not in the dot-files. It is even possible to set up the mac so, that none of these dot files will be created. In such a case, the Mac forgets, how the file is displayed. E.g. if you move a file on the desktop, it would be forgotten, if you access the desktop the next time.
The files have nothing to do with the old Mac format, they a new in OS X, there has been a different system in Classic, what you are talking about. The files which are containing the data are the same as on Windows.
So why does every source I've ever read say you're incorrect and that's why mac TT and T1 fonts cannot be used on Windows? Perhaps I'm wrong about those files starting with. being the resource forks, but the O kb files are old mac format fonts, and Windows is looking at the data fork only, which is empty because Apple for reasons I've never seen explained put the font data in the resource forks.
I just did a google search for this, and came up with osx - Why are dot underscore ._ files created, and how can I avoid them? - Ask Different which seems to indicate these are the equivalent of the resource fork in OS X.
Late to the game, but I know from experience that the 0 KB files ThinkingWeasel refers to all translate to 2 part Mac PostScript Type 1 fonts. Myriad, Stone, and Univers Cond Screen Fonts all would be the bitmap files and MyriaRom, StoneSanBolIta, UniveCon, and UniveConLig are the PostScript printer outlines files associated with the bitmap files. The bitmaps are what show up in the program font menus which then reference the printer outlines files which contain resource forks where the PS info for printing and exporting to PDF, etc resides. Probably what Peter was referring to without going into as much detail.
In any event, seeing PS printer font files with 0 KB sizes indicates to me the files at one time or another were copied onto a non-Mac drive where the resource forks were not supported and therefore lost, resulting in corrupted and useless printer font containers. Bringing them back onto a Mac would still not work because once the file is stripped of its resource fork, there's no bringing it back short of another copy with resource fork intact. Regarding the 0 KB size of the bitmap files, that's a new one on me. The bitmap info isn't stored in a resource fork in those files, so losing the resource fork shouldn't really affect the bitmap info in the data fork. Not sure how a bitmap font file would end up at 0 KB. Bottom line, those 0 KB files are useless and can't be repaired, may as well throw them away and look for copies.