[Chimera-users] on chimera saved PDB file

Dear All, By chimera I have saved a PDB file, but at the end of the saved PDB there are following sentences which I do not understand: CONECT 3 2 4 17 CONECT14560145591456114574 CONECT29117291162911829131 Will you please explain it to me the meaning of "CONECT 3 2 4 17" and the other 2 sentences? And why there is no space in "CONECT14560145591456114574"? Smith