PUG INFO:

Willoughby Pugs were developed by Lord Willoughby d'Eresby and had what is today considered a "smutty coat" because it had a mixing of fawn and black hairs in it. The color has been described as "stone fawn." The heads of these dogs were almost entirely black and they had wide traces, and even saddle marks on their backs (dark patches of hair shaped like the saddle of a horse). Their bodies were thin, and leggy. Mops and Nell were two prominent Willoughby Pugs that can be found as ancestors in Pug pedigrees even today. 

Morrison Pugs, in contrast, had rich apricot-fawn colored coats and stocky, cobby bodies. The trace on their backs was very light brown rather than black, and the coats had few, if any, black hairs in them. This line is much more in line with the modern Pug of today. Punch and Tetty were the foundation dogs of the Morrison line. It's not uncommon to hear dogs referred to today as "Willoughby" or "Morrison" type - referring to the darker color of the Willoughby, and the lighter color of the "Morrison."