. Elementary text-book of zoology. Gonotome. Metapleural Atrium. Ventral Muscle, said that one pair of pre-oral somites arise from the anterior end of the archenteron, a second pair behind these, called the collar-sacs, and a third pair at the posterior end laterally to the blastopore. The pre- oral pair form the head-cavity (right) of the larva and the pre-oral pit (left). Each of the collar-somites divides into a dorsal portion, which forms the first myomere muscle, and a ventral part forming the meta- pleural cavity. Lastly, the posterior somites divide up to form a great number of
. Elementary text-book of zoology. Gonotome. Metapleural Atrium. Ventral Muscle, said that one pair of pre-oral somites arise from the anterior end of the archenteron, a second pair behind these, called the collar-sacs, and a third pair at the posterior end laterally to the blastopore. The pre- oral pair form the head-cavity (right) of the larva and the pre-oral pit (left). Each of the collar-somites divides into a dorsal portion, which forms the first myomere muscle, and a ventral part forming the meta- pleural cavity. Lastly, the posterior somites divide up to form a great number of mesoblastic somites: so far as is known, they alone are found in Ascidia. The three pairs evidently correspond to the three archimeric seg- ments of Balanoglossus and the other Archiccelomata, and the metameric segmentation of the Chordata is clearly produced by secondary segmen- tation of the posterior segment or 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 Masterman, Arthur Thomas. Edinburgh, E. & S. Livingstone
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Keywords: ., bookcentury1900, bookcollectionbiod, bookdecade1900, bookyear1902
