Why does Finder see volumes which are not under /Volumes?

If I navigate as high as possible in Finder (under 10.10.2, but this did not appear only recently), I see this window, with many volumes which are long unmounted, ejected and erased. But if I tried to look around in the Terminal to potentially delete these, it only found the reasonable ones:

Laszlo-Sandors-MacBook-Pro:Volumes laszlosandor$ ls -la
total 24
drwxrwxrwt@  5 root          admin   170 Dec 28 09:04 .
drwxr-xr-x  47 root          wheel  1666 Dec 26 10:57 ..
-rw-r--r--@  1 laszlosandor  admin  6148 Jul 17 18:33 .DS_Store
lrwxr-xr-x   1 root          admin     1 Dec 26 10:51 Macintosh HD -> /
drwxrwxrwx   0 root          wheel     0 Dec 28 10:51 MobileBackups

Disk Utility only sees Macintosh HD.

What is going on, and what is there to do?