Evolution and Functional Morphology of the Proboscis in Kalyptorhynchia (Platyhelminthes) - PubMed (original) (raw)

Fig. 2

Musculature involved in feeding movements. Unless otherwise noted, the anterior end is toward the top of the plate. (A) Relaxed conorhynch proboscis, showing internal and external musculature; fixators of the proboscis and dilators of the proboscis-sheath shown only on the right and proboscis-protractor and integumental retractor shown only on the left; (B) Contracted conorhynch proboscis, showing epithelium of sheath and terminal cone, contracted internal longitudinal muscles (internal circular muscles not shown), and “hardened epithelium” (arrows) of the terminal cone near the juncture; Diagram of schizorhynchid proboscis-tongues showing musculature in longitudinal section (C) and cross-section (D); (E) Anterior tip of the body in Carolinorhynchus follybeachensis, with confocal stack showing body-wall muscles (circular, longitudinal, and helical); (F) Region between the brain and the pharynx in Proschizorhynchus sp., lateral view from left, confocal stack stained for muscles and nuclei; (G) Anterior end of Cheliplana (n.sp. “blind october”), lateral view from left side, confocal stack stained for nuclei, muscles, and cilia; (H) Proschizorhynchus “shaunae”, body-wall musculature near pharynx, confocal stack stained for muscles, anterior to right, viewed from right, position of pharynx indicated by imposed oval, arrow indicates position of pharyngeal lumen and points toward the mouth; note the oblique muscles in the body-wall (arrowheads); Diagram of contracted schizorhynchid proboscis-tongues in longitudinal section [I] and cross-section [J]; note that contraction of the radial muscle elongates and flattens the tongues; Diagram of relaxed [K] and contracted [L] proboscides in Karkinorhynchus; note elongation of the tongues due to contraction of radial muscles and that contraction of radial muscles inserting on medial portion of hook-bases could adduct the hooks (L). BR, brain; CE, cone-epithelium; DI, divaricators; DIL, dilator muscle; FI, fixator muscles; H, hook; ICM, internal circular muscles; ILM, internal longitudinal muscles; IR, integumental retractor, JU, juncture; M, mouth; NS, nucleus of proboscis-sheath; P, proboscis; PCS, post-cerebral septum; PH, pharynx; PHC, pharyngeal cavity; PP, proboscis-protractor; PR, proboscis-retractor; PS, proboscis-sheath; RM, radial muscle; S, septum. Scale bars: 2E, 100 µm; 2 H, 30 µm. Figures 2A, B adapted from Meixner (1938); Figures 2C, D, I, J, K, L adapted from Karling (1961). (This figure is available in black and white in print and in color at Integrative and Comparative Biology online.)