Unsegmented worms with thin flat bodies. Majority of species are parasitic (flukes and tapeworms). Most free-living flatworms are small and inconspicuous, but a few local species are larger, often with striking markings. Flatworms glide about using mucus & cilia as well as muscular undulations of their bodies. Most are predators of small invertebrates; their gut has but a single opening. Despite the general simplicity of their body structure, flatworms possess complex hermaphroditic reproductive systems. ~20,000 species.
Eurylepta californica Hyman, 1959
Phylum Platyhelminthes, Class Rhabditophora, Order Polycladida, Family Euryleptidae
Oval worm with flared tentacles bearing black & red marks at their base; length to 30 mm. Body grayish white with narrow mid-doral white line and scattered crisscrossing pattern of dark lines with scattered white spots.
Uncommon and cryptic, under cobbles and amongst low-lying red algae. Little is known about this species; congeners reported to feed on ascidians.
Geogr. Range: central California
Similar species: Pseudoceros montereyensis has black spots rather than crisscrossing lines and a black line around its lateral margin.
Pseudoceros montereyensis Hyman, 1953
Phylum Platyhelminthes, Class Rhabditophora, Order Polycladida, Family Pseudocerotidae
Large oval worm with ruffled margin; 40 mm long. White with mid-dorsal black line tinged with red; continuous black line around margin except between anterior tentacles; dorsum speckled with elongate black marks and fewer white spots & red flecks.
Uncommon and cryptic, under cobbles and amongst low-lying algae. Little is known of its biology, although congeners are reported to prey on compound tunicates.
Geogr. Range: central California; also reported from Oregon as well as southern Calif.
Similar species: Eurylepta californica has criscossing black lines instead of spots & lacks black line around lateral edge of body.