PLATE 3 
EXPLANATION OF FIGURES 
14 Club cells in the epidermis from the side of the tail. Zenker; Ehrlich’s 
haematoxylin and eosin. X 178. 
15 Three cells of the cuticular layer together with two replacing cells seen 
in longitudinal section, showing perpendicular striae, secretion plates (in sur- 
face view and in section), and secretion granules. Kleinenberg; Weigert’s 
resorcin-fuchsin. 733. ; 
16 The epidermis of the gular fold in perpendicular section, showing the 
reduction in the number of cell layers and a well-developed goblet cell. Klein- 
enberg; Ehrlich’s haematoxylin and eosin. X 405. 
17 Early stage of a developing gland from the dorsal side of the tail. The 
epidermal cells are seen entering the dermis along a perpendicular bundle of 
connective tissue. No intermediate spongy layer is present. The two compact 
dermal layers lie close together. Kleinenberg; Ehrlich’s haematoxylin and 
eosin. X 340. 
18 Later stage in the development of a gland in the region of the tail. The 
bud is solid. Mitoses in gland and in epidermis. Kleinenberg; Ehrlich’s haema- 
toxylin and eosin. X 340. 
19 Median longitudinal section of a developing granular gland from the 
region of the dorsal edge of the tail. A distinct lumen is present. The epi- 
thelium is definitely differentiated and considerable secretion has been produced. 
Kleinenberg; Ehrlich’s haematoxylin and eosin. X 340. (Successively later 
stages appear in fig. 24, pl. 4, and fig. 13, pl. 2.) 
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