Is this sentence correct?

[rai chu]

So I started reading the second Harry Potter when I read something that I suspected was incorrect. Now I'm not the best at English, so could someone clarify this for me?

I don't know if I'm reading wrongly but it just doesn't look right to me, maybe a missing word or is it meant to be like this?

moaning myrtle was crying noisily in her cubicle, but they were ignoring her, and she them

 

[Meadow337]

It is perhaps not the most elegant sentence construction but it's not incorrect.

Moaning Myrtle was crying
noisily in her cubicle; but
they were ignoring her,
and she [was ignoring] them.

The part in brackets is redundant and therefore unnecessary to put it in.