Integumentary muscles Extrinsic Integumentary muscles: 1. Platysma - derived from the _________ 2. Cutaneous trunci - derived from _______ and _______ 3. Sphincter coli in birds - derived from the ________ 4. Costocutaneous muscles in snakes - ________ Electric Organs: 5. Specialized blocks of mm, derived from ______ mm or ____ produce a jolt of voltage.