Green-striped chiton (Chiton vigulatus), brown chiton (Chiton articulatus), black chiton (Chiton stokesii), and heath's chiton (Stenoplax heathiana) were observed in the Gulf of Califonia: Puerto Penaso, Mexico, Station Beach to determine the size, abundance buy rock type and size, and tidal zones inhabited. Chitons were found exclusively on basalt rocks. More chitons were found per rock in lower/middle zone III and the largest chitons were found in lower zone III and high zone IV. Rock size and abundance of chitons per rock were inversely proportional. There was a positive relationship between length of chitons and rock size. Overall, low zone III contained the most chiton species. The green striped chiton was the most prevalent and the most dominant spices throughout the high and low zone II. Black and striped chitons were found in low zone III and one brown chiton was found in zone IV. Home Works Cited Layout & Associated Images Designed by Ariel Anderson