Coat of arms of Davy

The blazon

sa. on a fesse ar. betw. three dragons heads, erased close to the head, or, as many cinquefoils of the field. — Crest,atalbot s head, erased, ar. ducally crowned, collared, and eared, or.

A blazon is the description of a coat of arms in the technical language of heraldry. The drawing comes from that text, and from nothing else.