Figure 5.1: Micrographies of the body wall of P. prudhoei. A: dorsal epidermis. B: ventral epidermis.
C: parenchyma.



Musculature and Locomotion: P. prudhoei is a large turbellarian and uses not only cilia but also body movements for locomotion. For that reason, it has a well developed musculature, with multiple layers of circular, longitudinal and diagonal fibers forming a complex arrangement (Ruppert et al, 2004) (Fig.5.2).


Figure 5.2: Locomotion of P. prudhoei. The big arrow indicates
the direction of the movement and the small arrows
incate the undulations of the body margins.

Nervous and Sensory System: Polyclads have a diffuse, netlike nervous system with a ringlike brain and longitudinal nerve cords that join the nerve nets (Fig. 5.3) (Ruppert et al, 2004). Pseudoceros have pigment-cup ocelli organized in clusters over the brain (cerebral eyes) and in the tentacles (pseudotentacular eyes) that detect the presence and absence of light (Fig. 5.4) (Sopott-Ehlers,1991).

Figure 5.3: Netlike nervous system of P. prudhoei. Adapted from Ruppert et al (2004).



Figure 5.4: Cerebral and pseudotentacular eyes of P. prudhoei.
Adapted from  Newman and Cannon (1998) and Ruppert et al (2004).


Digestive System: P.prudhoei has a long protrusible plicate pharynx used for feeding and its intestine is blind (has only one aperture for the exterior, the mouth) (Fig.5.5 A and B). Also, the gut is highly branched and these lateral cecae form a gastrovascular system that helps distributing nutrients for the margins of the body (Ruppert et al, 2004).

Figure 5.5 A and B: Ventral surface showing the position of the pharynx,
male and female pores in P. prudhoei. Adapted from  Newman and Cannon (1998).