. The Annals and magazine of natural history; zoology, botany, and geology. Dr. A. Korotneff on Poljparium ambulans. 217 turned away. In this respect, therefore, Polyparium makes no special exception. Notwithstanding all this, it is necessary to show why the change which we find in the strength of the muscles in Poly- parium has been brought about. This question may be decided upon a mechanical principle. We have seen that the transverse bands [) project strongly into the interior of the gastral cavity, pass over with their fibres to the side- wall (), and in this way form an arch, the p
. The Annals and magazine of natural history; zoology, botany, and geology. Dr. A. Korotneff on Poljparium ambulans. 217 turned away. In this respect, therefore, Polyparium makes no special exception. Notwithstanding all this, it is necessary to show why the change which we find in the strength of the muscles in Poly- parium has been brought about. This question may be decided upon a mechanical principle. We have seen that the transverse bands [) project strongly into the interior of the gastral cavity, pass over with their fibres to the side- wall (), and in this way form an arch, the points of fixation of which are to be sought laterally upon the side-wall. During movement, in the creeping of Polyparium, the trans- verse fibres are the most active, and when they contract they must, as in .the bent bow, widen the lumen of the interior chamber (fig. III.). If we could imagine that the above-men- tioned transverse bands projected, not into the interior chamber Fig. Til. a, interior chamber ; h, intermediate chamber ; , side-wall; st. I, supporting lamella; , transversa muscular bands; , longi- tudinal muscles. but into the intermediate chamber, then the interior chamber (a) would be closed by their contraction. But we must con- sider that the nutrition of the animal must depend uncon- ditionally upon its movement; the animal, or the colony, only creeps in order to obtain nourishment, and therefore during locomotion the buccal aperture must remain wide open, in order that the food met with may pass directly into the stomach. Thus it becomes clear that the occurrence of the transverse bands in the interior chamber and of the ver- tical musculature in the intermediate chamber is not only Ann. ds Mag. N. Hist. Ser. 5, Vol. xx. 15. 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 Lo
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