Strange files in database directory

[slickdawg]

Can anyone tell me what these files are? They are in the directory for my vbulletin database.

-rw-rw---- 1 mysql staff 1024 Mar 24 21:58 #sql-2d45_1901c.MYI
-rw-rw---- 1 mysql staff 1024 Mar 24 22:30 #sql-2d45_19143.MYI
-rw-rw---- 1 mysql staff 1024 Mar 24 22:42 #sql-2d45_191a6.MYI
-rw-rw---- 1 mysql staff 1024 Mar 24 22:52 #sql-2d45_191ea.MYI
-rw-rw---- 1 mysql staff 1024 Mar 25 15:40 #sql-2d45_1b16d.MYI
-rw-rw---- 1 mysql staff 2048 Mar 26 22:07 #sql-2d45_23609.MYI
-rw-rw---- 1 mysql staff 2048 Mar 26 22:13 #sql-2d45_236c5.MYI
-rw-rw---- 1 mysql staff 18432 Mar 26 22:29 #sql-2d45_2378f.MYI
-rw-rw---- 1 mysql staff 18432 Mar 26 22:30 #sql-2d45_237be.MYI
-rw-rw---- 1 mysql staff 18432 Mar 26 22:34 #sql-2d45_237fd.MYI
-rw-rw---- 1 mysql staff 18432 Mar 26 22:46 #sql-2d45_238a2.MYI