Plural of brachycephaly; multiple instances or cases of the condition of having a short, broad skull.
From Greek brachycephalos + English plural -ies, creating a Latinized English plural form for abstract or countable instances.
The sheer number of different plural and adjectival forms for this concept shows how scientific terminology can become bloated and redundant—modern science would just say 'short skulls' and move on.
Complete word intelligence in one call. Free tier — 50 lookups/day.