. The American journal of anatomy . th them. Fluctuations in the amount of progress attained by the rightand left branches of the duct at any given moment during thecritical stages of their development are not infrequent; indeedthere appears to be a reciprocal action, for when one is large andlong, or well represented in the number of its anlagen, the otheris only scantily represented. All transition stages show thesevariations to a greater or lesser degree, but especially favorableexamples are series 103 and 191 (21 mm. embryos), which can beregarded as complements of each other, the former b
. The American journal of anatomy . th them. Fluctuations in the amount of progress attained by the rightand left branches of the duct at any given moment during thecritical stages of their development are not infrequent; indeedthere appears to be a reciprocal action, for when one is large andlong, or well represented in the number of its anlagen, the otheris only scantily represented. All transition stages show thesevariations to a greater or lesser degree, but especially favorableexamples are series 103 and 191 (21 mm. embryos), which can beregarded as complements of each other, the former being promi-nently dextral, and the latter sinistral in lymphatic growth. Inseries 103 the right limb of the duct extends as an unbroken chan-nel far back into the postcardinal division of the thoracic region,but the left limb is just visible in its earliest rudiments as a fewminute and isolated spaces. In series 191, on the contrary, wemeet with a complete reversal of conditions so that the descrip- 436 OTTO F. KAMPMEIER 6b m IS***. .^ — lis Fig. 12 Transverse section taken immediately posterior to the left Cuvierianduct in a 20 mm. pig embryo (series 194, slide 29, section 4), X 150. 4d, isolatedlymphatic spaces in the right thoracic duct line; 6b, postcardinal veno-lymphatics;lid, lis, right and left postcardinals; 13, aorta; 17, oesophagus. (Reconstruction,fig. 29.) tion of the right thoracic duct limb of series 103 applies withalmost equal force to the left limb of this embryo, and vice versa.(B) Postcardinal division. In the region of the postcardinalveno-lymphatic channels the discontinuity of incipient lymphaticanlagen and their origin in situ from the mesenchyme can beplainly demonstrated. In a destined course and at intervals,though not metamerical in sequence, spaces and fissures are pres-ent in the evenly meshed tissue along the channels instance, they can not be mistaken in figure 12 (series 194-20 mm.), where two of them are shown as clear crevice-l
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1912
