Canon EOS C300 Instruction Manual page 16

Names of Parts
#
16
32
32 START/STOP button (A 49)
33 # EF Lens mount index (A 32)
34 # EF-S Lens mount index (A 32)
35 # Lens release button (A 32)
36 # EF Lens lock pin (A 32)
37 # EF Lens mount (A 32)
38 # EF Lens contacts (A 32)
$
39
33
40
34
35
41
36
37
38 42
39 $ PL Lens mount (A 34)
40 $ Bayonet ring handles (A 34)
41 $ PL Lens index pin (A 34)
42 $ Bayonet ring (A 34)