372 DENDRITIC APPENDAGE OF UROGENITAL PAPILLA 



proper, exactly alike not only in shape and occurrence but also in the 

 fact that they are distinctively stained by Kleinenberg's hiematoxylin 

 solution. 



Let us next examine the glandular cells in the pits which form 

 such a characteristic feature of the appendage. As Figs. 20 and 21 

 show, they are uncommonly large cells, always filled u[) with finely 

 granular substance and containins: a sinçi;le oval nucleus in al)out the 

 middle of their length. In a section, they are seen standing side by 

 side in a single row along the bottom and sides of every pit and ex- 

 posing their heads directly into tlie c;ivity of the pit, although the 

 nuclei of the epidermal cells are seen here and there scattered over 

 them. A group of the glandular cells belijnging to one pit forms a sort 

 of cup, more or less distinctly separated from neighbouring groups or 

 cups by the intervening epidermal cells, capillaries, etc. (Figs. 19 and 

 20); so thjit the glandular cells do not form a single continuous sheet 

 as supposed by Brock. It is evident from the above description that 

 the secretory product of these glandular cells is discharged directly into 

 the cavity of the pit tlu-ough the interruptions of the epidermis. In 

 specimens killed with chromic acid or chromo-acetic acid, the granular 

 contents are well stained with alcoholic or watery solutions of such 

 aniline dyes as eosin, methyl-blue, and sattranin, but do not absorb 

 Kleinenberg's haematoxylin solution which differentiates the slime 

 cells. 



In the body pro[)er as well as in the Ijasal portion of the stalk, 

 there are found, as I have mentioned above, instead of such true 

 glandular cells, a nund)er of large ductless goblet-cells at the inner 

 part of the epidermal layer (Figs. 18 and IS)). In the fully developed 

 stage, these two kinds of cells are distinguished from each other by 

 the following points : — 



a) The glandular cells of the appendage form definite groups, 



