564 WALLACE. [Vol. VIII. 



polygonal cells on the surface. These are much larger than 

 the preceeding, the nuclei measuring 5 /x in diameter and the 

 entire cell having an average diameter of 12 /it. The nucleus 

 takes a faint stain and has a distinct but not conspicuous 

 nucleolus, (c) Beneath these, and differing from them only in 

 form, are the elongated cells which are sometimes ovate, some- 

 times spindle-shaped, and as the cell increases in length the 

 nucleus is seen nearer the upper end rather than at the center. 

 The cells are 35/u. in length and the round nucleus has a 

 diameter of 7/u,. (d) Resting on the basement-membrane and 

 arranged with comparative regularity, are the columnar cells, 

 20 /x in length and containing a nucleus j [x. in diameter. 

 Neither these nor the elongated cells have a distinct nucleolus. 

 The outline of the cell-wall is sometimes rounded at the top, 

 but more often sends a prolongation into the interstices of the 

 elongated cells lying above, (e) At regular intervals in the 

 polygonal layer of cells and projecting through the superficial 

 layer are the mucous cells, usually so full of well-stained 

 mucin that little idea can be had of their general character 

 beyond their shape and striated contents. If, however, they 

 are carefully taken from living tissue and freshly stained with 

 methyl green, the structure becomes clear. Globate or oval in 

 form, they attain a length of 30 /* and have a large, bright 

 nucleus at the base lO/u, in diameter. The protoplasm is 

 vacuolated and sends protoplasmic strands through an aperture 

 at the top, the vacuoles, no doubt, being filled with transparent 

 mucin. (Fig. Ill, a) In dead cells found in the secretion of 

 the gland, the exact form of the aperture can be distinctly made 

 out and is usually oval with a perfectly smooth edge, (f) The 

 huge clavate cells vary somewhat in shape according to their 

 position, the majority being rounded at the top with a tapering 

 base. In sections the contents of the cell seems to be an 

 evenly stained, homogeneous substance while in specimens 

 macerated for twenty-four hours in nitric acid or Haller's Fluid 

 distinct spherules are abundant, which are probably dissolved 

 or broken up by long treatment. In Fig. II, the secretion of 

 the cell is shown shrunken away from the cell-wall, leaving 

 behind a thin layer of protoplasm in which is suspended, 



