Craniate with well-defined heads, thus excluding members of the chordate subphyla Tunicata (tunicates) and Cephalochordata (lancelets), but including Myxini, which have cartilaginous skulls and tooth-like structures composed of keratin. Craniata also includes all lampreys and armoured jawless fishes, armoured fish, sharks, skates, and rays, and teleostomians: spiny sharks, bony fish, lissamphibians, temnospondyls and protoreptiles, sauropsids and mammals. The craniate head consists of a brain, sense organs, including eyes, and a skull. In addition to distinct crania (sing. "cranium"), craniates possess many derived characteristics, which have allowed for more complexity to follow. Molecular-genetic analysis of craniates reveals that, compared to less complex
Things Which Have Never Yet Been Done was shot with a handheld camera by the episode's director, TJ Scott, with Maslany and Outerbridge improvising the dialogue and use of props. The subsequent shot of the barn on fire was created by the visual effects company Intelligent Creatures. The title of the final two episodes, "Things Which Have Never Yet Been Done" and "By Means Which Have Never Yet Been Tried", are taken from a Francis Bacon quotation in his philosophical work "Novum Organum": "It would be an unsound fancy and self-contradictory to expect that things which have never yet been done can be done except by means