Pamphlets on Parasitology Volume 236 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1898 Excerpt: ...Where fibres join end to end there is an irregular jagged interlocking, which looks like the line of a break across the grain of a board, and doubtless is to be explained on the same principles. The fibres have a structure similar to that of the circular muscles, but are exceedingly variable in the relative amount and arrangement of striated and granular substance. Some exhibit a complete cortical layer with radiating longitudinal markings, within which, as a medullary portion, the granular protoplasm is confined with the nucleus; others show a large mass of granular protoplasm, with the striated substance variously arranged, UNIVERSI1 and perhaps limited to two small bands. Muscle fibres of the former type, but with the addition of an external granular mass, in which the nucleus is imbedded, about the middle of their lengths, are most frequently met with. Figs. 7, 8, and 11 show a few examples. The inter-segmental septa are composed of more or less parallel dorso-ventral muscles, which form thin sheets, arising by one or two roots, from the ends of the longitudinal fibres. Where best developed the component fibres are bound together by cross-slips, much as are the circular body muscles. Septa are aborted between the first four somites, which freely communicate; but remnants remain as a few delicate slips which guy the alimentary tract to the body walls. They are well developed between the sexual somites. The musculature of the posterior sucker is complex, and well adapted to secure strength and mobility. The circular muscles undergo little change; but the longitudinal split up, by the branching of individual fibres, into a set which are the direct continuation of the body longitudinal fibres, a second set which pass dorso-vent rally across the body cavity, ..