Bob Naismith created the initial design for the Space Marines, which was modified by Jes Goodwin and Aly Morrison when the design was translated to models. The original Space Marines in Power Armor had helmets with prominent conical snouts, which were based on single-filter gas masks used by soldiers in World War 1; and not medieval "hounskull" helmets as some may believe. This original design is popularly remembered as the "beaky" design, and in the lore it is known as "Mark VI Corvus", and the beaky helm is occasionally found in subsequent sets of Space Marines. Jes Goodwin designed the second edition (1993) "Mark VII Aquila" design of Power Armor, where the helmet's beak was replaced by a flat grill, and the chestplate features a winged skull. With the eighth edition (2017), Games Workshop introduced the Primaris Space Marine models that are slightly taller than previous designs of Space Marines in Power Armor.