. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. 252 Prof. M'lntosh's Notes from the apparently uniform, and contain mud rich in organic remains. The former or stomachal region enters the following or intestinal region by an aperture which is thrust backward as a cone. Moreover, the walls of the organ undergo a struc- tural differentiation, for a short distance before reaching the aperture (text-fig.) they become finely reticulated and dotted as if formed of muscular or erectile tissue {ec), whilst the lining of the tube con
. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. 252 Prof. M'lntosh's Notes from the apparently uniform, and contain mud rich in organic remains. The former or stomachal region enters the following or intestinal region by an aperture which is thrust backward as a cone. Moreover, the walls of the organ undergo a struc- tural differentiation, for a short distance before reaching the aperture (text-fig.) they become finely reticulated and dotted as if formed of muscular or erectile tissue {ec), whilst the lining of the tube consists of the same mucous membrane as in front. Further, the adjoining circular fold of the diaphragm {spt. 3) is provided with a similar, though thinner, layer of the same tissue (ec), which likewise. Longitudinal section of the alimentary apparatus at the third septuu), spt. 3, showing traces of the special muscular layer, ec, enveloping the posterior wall of the stomach and its sinuses, and continued over the valvular region, veil. ; hp., hypoderm ; , ccelomic corpuscles ; ing., mucous glands. occurs in two of the folds of tlie organ in front of the foregoing. This tissue is apparently muscular, and its minute structure is interesting as showing the peculiar muscle-cells with their granular contents and nuclei which stud the free border of the muscle. Ziircher "^ has given a good description and figures of the structure of this tissue. It evidently controls not only the wall of the canal but the blood-sinus on its outer surface, and thus may have con- siderable effect on the main trunks proceeding forward to the branchiae. The ccelomic corpuscles often form a * Op. cit. p. 203, and figs. 33 & 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 London, Taylor and Francis, Ltd
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