AUTHOR S ABSTRACT OF THIS PAPER ISSUED 
BY THE BIBLIOGRAPHIC SERVICE, MARCH 14 
EXPERIMENTS ON THE EFFECT OF REMOVAL OF 
THE PRONEPHROS OF AMBLYSTOMA 
PUNCTATUMi 
RUTH B. ROWLAND 
shorn Zoological Laboratory, Yale University 
TWENTY-THREE FIGURES 
CONTENTS 
Introduction 355 
Material, methods, and normal development 361 
Bilateral excision of pronephric rudiments 365 
Mode of operation 365 
Effect of bilateral removal 366 
Unilateral excision of pronephric rudiments 371 
Postoperative elfect on the embryo as a whole 372 
Effect of unilateral excision on the remaining pronephros 372 
Effect of unilateral excision on the glomerulus 377 
Effect of unilateral excision on the other components of this system . . . 377 
Effect of removal of the heart on the development of the glomerulus 381 
Summary and conclusions 382 
Literature cited 384 
INTRODUCTION 
The common occmTence, among the lower orders of verte- 
brates, of a more or less persistent head kidney or pronephros 
has led to the accumulation of a very comprehensive literature 
on this subject from the standpoint of pure morphology. Little 
evidence has been furnished in any group, however, of the role 
which these organs play in the life of the embryo. 
Price ('10), working on the head kidney of one of the myxi- 
noids, Bdellostoma stouti, a form in which it persists throughout 
adult life, follows up his earlier descriptions of the development 
^ A preliminary reoort of the results obtained was published in 1916. (How- 
land, R. B., '16. On the Effect of Removal of the Pronephros of the Amphibian 
Embryo. Proc. Nat. Acad. Sc, vol. 2.) 
355 
