The American journal of anatomy . Fig. 1 Diagram drawn from a reconstruction of the Aeins in the cervical andupper thoracic regions of a chick embryo of five days and twenty hours. Rightside. 1, Precardinal vein; 2, postcardinal vein; 3, duct of Cuvier; 4, intersegmental(dorsal somatic) veins; 5, lateral group of venous islands (derivatives of and addi-tions to which are represented by stippled areas in succeeding diagrams). There is a general tendency on the part of the intersegmentalveins (4) toward a division into medial and lateral medial branches run close to the aorta and ar
The American journal of anatomy . Fig. 1 Diagram drawn from a reconstruction of the Aeins in the cervical andupper thoracic regions of a chick embryo of five days and twenty hours. Rightside. 1, Precardinal vein; 2, postcardinal vein; 3, duct of Cuvier; 4, intersegmental(dorsal somatic) veins; 5, lateral group of venous islands (derivatives of and addi-tions to which are represented by stippled areas in succeeding diagrams). There is a general tendency on the part of the intersegmentalveins (4) toward a division into medial and lateral medial branches run close to the aorta and are obviouslythe dorsal somatic veins proper, being in this region the cervicalintersegmental veins (fig. 2, 4). The lateral branches arise inthe same general region in which the above mentioned vascular DEVELOPMENT OF THE JUGULAR LYMPH SAC 477. Fig. 2 From a photograph of a section through the cervical region of a chickembryo of five days and twenty hours (embryo from which the reconstructionrepresented in fig. 1 was made). 1, Precardinal vein; 4, intersegmental cervical(dorsal somatic) veins; 5, lateral group of venous islands (represented in fig. 1by stippled areas); 6, aorta; 7, cesophagus; 8, notochord. islands (5) are situated. Despite the fact that at this stagethere is a tendency toward a separation of the vascular channelsand islands into a medial group and a lateral group, they appar-ently all belong in the same category, namely, an aggregation of 478 A. M. MILLER vascular channels and islands in the mesenchymal tissue dorsalto the portions of the precardinal and postcardinal veins neartheir confluence to form the duct of Cuvier. All these channelsand islands are obviously venous in character, many of themfilled with nucleated red blood cells. Compared with the mammalian embryo, the conditions inthe chick at this st
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectanatomy, bookyear1901
