It says:
168
Tenth April 1850 Walshford
William
Boy
John Whincup
Mary Whincup formerly Kay
Farmer
The Mark of X John Whincup Father Walshford
[something] May 1850
Joseph Dixon Registrar
What's that [something] say there? Here is it in close-up:
I don't actually need to know for genealogical reasons, but I need to know for "damn you, Joseph Dixon!" reasons.
Yes, I did look up who the registrar of births and deaths was for the sub-district of Wetherby in 1850 because I couldn't read his name on the certificate either.