. Text book of zoology. Zoology. 154 Platyhelminths. its sheath. A long muscle^ the retractor, passes from its inverted end to the sheath, and this pulls in the everted organ {see Fig. 115 D). Its function is defensive and prehensile; it is not connected with the digestive tract. This begins in front and ventrally (behind the proboscis pore) in a slit-like mouth, and runs through the body as a canal, furnished usually with small lateral evaginations, and opening in the anus at the posterior end. m an Dp DQ. Fig. 115. A Sketch of a Nemertine, showing the nervous system, B do. with blood vascula
. Text book of zoology. Zoology. 154 Platyhelminths. its sheath. A long muscle^ the retractor, passes from its inverted end to the sheath, and this pulls in the everted organ {see Fig. 115 D). Its function is defensive and prehensile; it is not connected with the digestive tract. This begins in front and ventrally (behind the proboscis pore) in a slit-like mouth, and runs through the body as a canal, furnished usually with small lateral evaginations, and opening in the anus at the posterior end. m an Dp DQ. Fig. 115. A Sketch of a Nemertine, showing the nervous system, B do. with blood vascular system, C ditto with gut and proboscis, D ditto front end with everted proboscis. Diagrammatic, a Anus, c ciliated groove, aa gut, g poison gland, I lateral vessel, m retractor muscle, r probscis, ro proboscis opening, rs proboscis sheath, s lateral nerve cord, t transverse vessel.—Orig. The nervous system is very like the usual flatworm type; the proboscis sheath passes between the cerebral commissures. From the cerebral ganglion of either side arises a lateral nerve, running backwards, and containing numerous nerve-cells; the two cords are often connected by delicate transverse commissures, passing above and below the alimentary canal, and from them many nerves arise. The excretory organs are similar in structure to those of other Platworms. Besides the ciliated grooves and eyes. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Boas, J. E. V. (Johan Erik Vesti), 1855-1935; Boas, J. E. V. (Johan Erik Vesti), 1855-1935. Lehrbuch der Zoologie. London, Sampson Low, Marston
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1896
