Thought 116a was Carriage dog
116a) Old term for a Dalmatian dog(8,3)
Yet this does not fit in with 117 down which think is mum making the first letter of the second word M.
117d) the Female parent of a mammal.
125 across- last letter of 117d is M as 125 across answer is Ruthenium.
Hope you can help this confused.com puzzler out. Cheers v much, Si