M33-281  1  Encircled stars                0.14
M33-281  2  Within shell                   0.14
M33-281  3  Other OB associations in field
M33-281  5  Background                     0.05
M33-640  1  Encircled stars                0.19
M33-640  2  Within shell                   0.19
M33-640  3  Partial shell in field
M33-640  5  Background                     0.05
M33-643  1  Encircled stars                0.10
M33-643  2  Within shell                   0.10
M33-643  3  Another shell (?) in field
M33-643  5  Background                     0.05
M33-Z86  1  In central HII                 0.24
M33-Z86  2  Within eastern shell           0.14
M33-Z86  3  Other OB associations in field
M33-Z86  5  Background                     0.05
M33-Z263 1  Encircled, within HII          0.20
M33-Z263 2  Within shell                   0.20
M33-Z263 3  Other OB associations in field
M33-Z263 5  Background                     0.10
M31-B2   1  Encircled, shell 1             0.55
M31-B2   2  Encircled, shell 2             0.57
M31-B2   3  Other OB associations in field
M31-B2   5  Background                     0.08