Thanks Sue, I agree it looks like a a transcription error. I'll apply for a copy of the entry as you suggest.

I can see now that "muem" is actually "Mason".

From another tip I have another possible record entry for the family in the 1891 Census :-

Living in 2 rooms at 6, Lord Street, Douglas are -
William Cowell Head 40 Plasterer Neither employer or employed b Douglas
Jane Cowell Wife 38 b Douglas
Edith Cowell Dau 16 b Douglas
Sarah Cowell Dau 12 Scholar b Douglas
Fanny Cowell Dau 10 Scholar b Douglas
William Cowell Son 7 Scholar b Douglas
Thomas Cowell Son 3 Scholar b Douglas
John Cowell Son 1 b Douglas

In this entry Father's profession & name, Mother's name, Place and Sarah's age all match up. However, some other items don't - e.g. Wiliam Cowell's age also children's names. It could be these are 2 different families.

I've seen from many other entries that the census information quality can be very variable so perhaps these are mistakes.