132 Journal of Comparative Neurology 



This tube appears in cross-section also as a mere group of 

 cells arranged as seen in Fig. 2, Plate VI, nl, epit etc. A series 

 of cross-sections shows this tube to consint of a mere grouping 

 of cells with an illy defined duct within. The cells are arranged 

 in a circular manner leaving this space within which opens above 

 into the groove and below into the lumen of the diverticle. This 

 is shown at a later stage in Amblystoma, Fig. 5, Plate VI, nl. 

 From the general cavity of the nose there projects a lumen into 

 this diverticle, which is continuous with the tube of the above 

 mentioned duct. This duct then passes laterad, dorsad, and 

 caudad as above described. The eye-ball, ey, is much reduced 

 comparatively, and shows roughly the reconstruction of the bi- 

 furcated opening of the naso-lachrymal upon the lower eye-lid. 

 In this figure (Fig. 1, 2, Plate VI) the tube is situated just be- 

 low the epidermis and can be followed for several sections quite 

 distinctly until it emerges upon the surface as a groove or fur- 

 row. See Fig. 1, nl and op, Plate XI. 



Under a high power the cell-walls may be discovered of 

 these epithelium cells as well as of the characteristic connec- 

 tive-tissue cells with which they are surrounded (Fig. 2, epit and 

 con, Plate VI). An outer layer of epithelium cells intervening be- 

 tween the true epithelium and connective-tissue cells have beome 

 flattened and adhere to the outer sides of this tube. See also 

 Fig. 5, epit and con, Plate VI. Surrounding it is, further, the 

 fibrous tissue which binds the tubular structure somewhat to the 

 skin beneath which it lies. Chromatophores line the skin here 

 very abundantly. See pig, Figs. 1, 2, Plate VI. This abrupt 

 change in the course of this duct appears almost entirely within 

 three or four sections (which are not more than 15-20 micro- 

 millimeters thick.) At this stage the lachrymal glands are not 

 developed to any extent, which accounts for, or correlates with 

 the undeveloped condition of the duct. As seen in the other 

 types the duct here also divides into two tubes for a short dis- 

 tance before entering upon the open surface of the lower lid {op, 

 shown also in Figs. 3, 4, Plate XI.) 



This diverticle, out of which the naso-lachrymal leads, may 

 be homologized with the smaller outer, upper diverticle found in 



