Tho Cutaneous Ghiuds of Coiiiuioii Toads. 335 



length of 2 to 3 mm. and the fore limbs, while well formed, were 

 not yet visible on the surface. The buds occurred in both the ventral 

 and dorsal epidermis of the body and limbs. A younger series, 

 whose body length was 6.5 mm. and whose hind limbs were merely 

 buds, showed no indication of gland formation (Fig. 5). It is in- 

 teresting to note that the gland buds arise just after the animal has 

 passed its most typical aquatic form, and appear at the same time 

 with other adult structures. 



Gradation of glands in adult. I have found buds of a similar 

 nature in the epidermis of the adult toad (Fig. 26). From this 

 point on a very completely gradated series of glands may be selected 

 (Figs. 27-41). The climax of the series, beyond which point degen- 

 eration may set in, we will term the mature gland (Figs. 14, 42, 

 58-a). The size of the neck, collar and walls of the acinus (ex- 

 cluding for the present the epithelium) reach, in the mature type, 

 their highest development. The elements which constitute the parts 

 are all present in the younger glands. They are developed in pro- 

 portion to the size and age of the glands. Throughout the series 

 a gradual change in the epithelium and in the secretion can be fol- 

 lowed. The production of poison granules in the secretion completes 

 its highest development. 



Batteries of glands. The great variation in the size and shape 

 of the glands and differences in location in the strata of the cutis 

 incident to their size, make it difficult to give a general description. 

 I shall, therefore, for convenience designate three strata or bat- 

 teries of cutaneous glands: (1) inner, (2) outer and (3) transitional 

 (Fig. 25, a, c, b). The glands occur singly in the ordinary skin of 

 the back, and singly or somewhat closely arranged in the ventral skin. 

 In warts, where they reach the largest size, they are closely grouped. 

 The glands in a given battery vary greatly according to the regions 

 of the body. 



(1) The glands in any region, whose bodies reach almost to the 

 inner loose stratum of the cutis, constitute the inner battery (Figs. 

 14, 25-a, 5S-a). The lumen of such a gland is completely filled with 

 secretion and is irregularly lined by naked nuclei rather than by a 

 cellular epithelium (Figs. 43-47). The extent of each wart is gov- 



