xr. B, » Garcia: Absentee of Kidneys in a Pig Embryo 



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dostratified, columnar, ciliated epithelium surrounded by a layer 

 of vascular, young connective tissue in many places richly in- 

 filtrated by lymphocytes. Between the section of the oviduct and 

 the rete ovarii, in the mass of tissue which represents the broad 

 ligament, several distinct mesonephric tubules, which are part 

 of the parovarium, were seen. 



The last 6 millimeters of the upper end of the right ureter 

 was embedded for examination. Sections from the lower end of 

 this piece of ureter showed a well-defined oval lumen lined with 

 transitional epithelium, the cells of which for the most part were 

 ovoid in shape. Their nuclei stained faintly and were placed 

 near the cell base. Surrounding this epithelium, two distinct 

 layers of tissue were seen; the inner coat, slightly the thicker 



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Fia 2. Section of upper end of ureter (ilsht). F^o. 3. Section of lower end of right ureter. 



of the two, appeared to be made up of young connective tissue 

 cells which were of irregular shape and showed collections of 

 lymphoid tissue in many places. The outer layer was made up 

 of fusiform cells more loosely arranged. In this coat numerous 

 blood vessels were seen. Sections taken higher up had smaller 

 lumen lined with transitional epithelium, the cells of which 

 appeared better stained and their outlines more distinct. The 

 surrounding connective tissue layers were looser in texture, the 

 cells becoming more starshaped and approaching more the char- 

 acter of mesenchymal cells. Higher up the ureter breaks up 

 into two or three solid cords of epithelioid cells surrounded by 

 loose mesenchymatous tissue, which now exhibits here and there 

 collections of lymphoidlike cells resembling to a certain extent 

 small lymph glands. In no section of the entire 6 millimeters 

 of ureter could we find any tissues which might in any way 

 suggest the slightest structure of the blastemal cap, which is 

 always present in normal cases (figs. 2 and 3). 



