154 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



longs to the series of the carbopyridic acids. There is also found a base, 

 leucomaine, which is analogous to the vegetable alkaloids. He denies 

 that the gland in Astacus contains uric acid. 



It is difficult to reconcile these diverse results. It is undoubtedly 

 true that the antennal glands eliminate certain ammonia compounds, 

 and it is also shown by Marchal ('92, p. 243), that one of their func- 

 tions is to rid the organism of the excess of mineral salts present in the 

 blood, and Kirch ('86) has found that in Astacus these organs contain 

 glycogen. Gerstaecker ('95, pp. 1009, 1010) concludes that, in view of 

 all these results, we must consider the antennal glands of Decapoda not 

 as closely analogous to a kidney, hut as excretory organs important in 

 the general metabolism ; and, by reason of recent work, that we must 

 concede the physiology of the antennal glands to be in many respects an 

 open question, the solution of which will require much research, and 

 that it is not wholly improbable that these glands, like the liver, are 

 subject to temporarily changing functions. 



This seems a fair and conservative statement, which expresses the pres- 

 ent state of our knowledge in regard to the function of these organs. 



The work represented by this paper was done during the years 

 1896-97 and 1897-98 in the Zoological Laboratory of Harvard Univer- 

 sity. During the year 1896-97 my work was aided by privileges af- 

 forded by a Morgan Fellowship in that University. I wish here to 

 express my indebtedness to Prof. E. L. Mark, Director of the Labora- 

 tory, for his kindness in many ways, and for his supervision and able 

 criticism of the work during its progress. I am also indebted to Mr. 

 Alexander Agassiz for the opportunity of working at his Newport Lab- 

 oratory during part of the summer of 1897, and for appointment to a 

 table at the United States Fish Commission Laboratoi-y at Wood's Hole 

 during the summer of 1896 ; to Hon. J. J. Brice, formerly United States 

 Commissioner of Fish and Fisheries, for courtesies extended at various 

 times at the Wood's Hole and Gloucester stations of the United States 

 Fish Commission ; and to Prof. F. H. Herrick and Dr. G. H. Parker for 

 the use of embryonic material of certain stages. 



Methods. 



The methods employed were different in the embryonic, larval, and 

 adult stages. 



In studying the finer anatomy of the adult organ, I have had re- 

 course to maceration, teasing, and serial sections. For sectioning, the 



