322 Effa Funk Muhsc. 



Stages of the Gland, other than the Mature 345 



Developing stages 345 



I. a, b, c, d, e 345-346 



II. f, g, h 347-348 



Degenerate forms 348 



One Khid of Cutaneous Gland— Its Purpose and History 348 



Purpose 348 



Production of secretion in relation to age 350 



Life history of the one kind of gland 352 



Literature 352 



How glands are replaced in the toad 354 



Gradation-, a proof of one kind 354 



Distribution of glands, a proof 354 



Proofs from warts with degenerative glands and from grow- 

 ing warts 355 



Conclusions 355 



Bibliography 358 



Plates 



General Inteoduction. 



The purpose of the present paper is to show that there is but one 

 kind of gland in the cutis of the common toads. The writer is con- 

 vinced that the several kinds of glands described by authors are but 

 different stages in the development of the same gland. Throughout 

 the paper, the reference is to the general integument of the body, 

 exclusive of modification in the region of the head, feet and cloaca. 

 It is principally the conditions in the adult toad that are under 

 consideration, but references are made to conditions in certain stages 

 preceding the adult, when a point may thereby be more clearly dis- 

 cussed. The structure of the epidermis and cutis in Batrachians 

 is more or less a matter of general knowledge, and the writer has 

 considered them very briefly, merely for ready reference while deal- 

 ing with the glands. 



I wish to express my grateful appreciation of the facilities placed 

 at my disposal by the Department of Histology and Embryology of 

 Cornell University, where the first material for this investigation 

 was prepared. The work was finished in the Department of Zoology 

 in Indiana University, and I am greatly indebted to Dr. C. H. 

 Eigenmannn and Dr. Charles Zeleny for valuable suggestions, and 

 criticism of the final report on the material examined. 



Material. Toads have been collected during this investigation 

 from three different localities. The first specimens (Bufo ameri- 

 canus) were taken at Ithaca, IsT. Y., principally at the breeding 



