Notoplana acticola

The Notoplana acticola species are commonly located on the undersides of cobble stones, boulders, and other mussel beds which are found in rocky intertidal areas. This intertidal area receives a systematic exchange of water. When they are collected for biological purposes, they are normally found in tidal pools. Notoplana acticola are commonly found in the Pacific Ocean off of the coast of North America, specifically California. == Behavior ==

The Notoplana acticola species is one of the most primitive animals that possesses a brain. When the reproduction process occurs, one flatworm will inseminate the other flatworm, forcing the individual to carry other's eggs. The reproduction process normally occurs in the summer season. Although flatworms are hermaphrodites, they can also switch between asexual and sexual reproduction. The process of asexual reproduction occurs through the fragmentation process, which results in regeneration of missing body margins. == Morphology/appearance ==

An adult Notoplana acticola can range from one to two inches in length. The flatworms appear to be a tan or gray color with a darker shade through the center of the body. A Notoplana acticola's body is wide on the anterior end and normally narrows towards the end of the body. The clusters are scattered throughout the body of the flatworm, including down the center band. Notoplana acticola have approximately sixty to eighty ocelli that are clustered on the dorsal tentacles. The ocelli are formed in two longitudinal bands that run alongside the cerebral ganglion. Each ocelli contains thirty to fifty photoreceptors which contribute to the dendritic process of cell pigmentation projections. == Body systems ==

Notoplana acticola's body wall is composed of sheets of smooth muscle that consists of longitudinal, transverse, and oblique layers that alternate throughout. Additionally, the muscle and connective tissue fibers rotate back and forth between the ventral and dorsal sides. The species' ventral and dorsal body walls can range from 35-40 microns in thickness. After the food is passed through the pharynx, the food then enters the gastrovascular cavity where it is distributed to provide nutrients to the flatworm. == Neuronal system ==

The brains of the free-living polyclad, Notoplana acticola, are considered true brains. The body of the flatworm is bilaterally symmetrical and it involves cephalization. In contributing studies, research presents that Notoplana acticola represents a stage in their evolutionary process that demonstrates that neuronal behavior occurs in the peripheral nervous system. In a specific study regarding nerve repair and behavioral recovery, brains were transplanted into decerebrated Notoplana acticola. The species neural system consists of a variety of nerve fibers in the central nervous system that are located on the anterior portion of the brain. The ventral and dorsal networks are formed by the nerve fibers, which resemble the nerve-net where information can be conducted and passed around. Research demonstrates the use of the flatworms nerve-net in assistance of locomotion. The locomotory waves begin at the anterior margin of the body and end at the posterior portion of the body. The majority of the locomotory waves are connected to the peripheral nerve nets. The locomotory waves present in this species are cultivated by the sheets of smooth muscle in the hydrostatic skeleton. == Feeding ==

The species was engaged in a study presented by The University of Chicago Press in which the Notoplana acticola was offered a brine shrimp. The brine shrimp was placed at the anterior margin of the Notoplana acticola, and the flatworm extended its body toward the shrimp. The portion of the body closest to the prey is the portion the flatworm utilizes to grip the prey and ingest into its midventral mouth. If the flatworm has been starved, it will lunge at the prey, grip onto it, and quickly ingest it. However, if the flatworm is fed daily, it attacks normally and ingests at a slower rate. The study demonstrates that Notoplana acticola can accept three to five brine shrimp and fully digest them in approximately five minutes, but will not feed again for close to an hour. If the prey is offered to the flatworm on the posterior lateral portion of the body, the flatworm will lift the end of the margin and grip the food. After gripping the food, a homolateral turn is followed to bring the anterior portion of the body in association with the food. This way, the food can pass through the anterior margin to the mouth for the flatworm to digest the prey. Compared to a decerebrate flatworm versus the normal flatworm there are different feeding behaviors. The brine shrimp was given to the decerebrated Notoplana acticola on the posterior margin portion of the body where the flatworm held on to the prey, but did not grip it. The prey was held at the posterior end of the body and was slowly transported to the mouth. When the brine shrimp was offered at the anterior end of the body the prey was swallowed and conveyed posteriorly into the mouth. The decerebrated flatworms will continue to accept brine shrimp with no limit. Along with brine shrimp, Notoplana acticola are known to feed on limpets, which include shelled mollusks, barnacles and worms. All flatworms are considered carnivores, which ingest prey that consists of small invertebrates. == References ==