This rather handsome Mabie Todd pen is neither a Swan nor a Blackbird, nor yet a Jackdaw. It’s just “The Abbey Pen”. I’ve been unable to find any explanation for it and this is the only one I’ve ever seen.
Wyvern made an Abbey pen in the 30s but I think that’s just a coincidence of names. The Wyvern pen was at the lower-cost end of their production, and this Mabie Todd Abbey Pen would have been expensive, going by the quality of construction and the amount of gold-plated trim.
It measures 12.6 cm capped, but it is a useful size posted at 15.6 cm. When it came to me it had no nib but I have fitted a Swan number two flexible medium stub. It writes like a dream.
Goodwriterspens's Blog 
You don’t say if there is a Mabie Todd stamping on the barrel. Is there one? Though the clip is certainly the style of MT and the diameter of the overall pen is very much redolent of the Eternal line of pens according to my old eyes…
Stuart
Yes, it is stamped ‘Mabie Todd’.