162 PROCEEDINGS OF THE ACADEMY OF [Feb., 



THE SPERMATOGENESIS OF SYRBULA AND LYCOSA, WITH GENERAL CON- 

 SIDERATIONS UPON CHROMOSOME REDUCTION AND 

 THE HETEROCHROMOSOMES. 



BY THOMAS H. MONTGOMERY, JR. 



The present paper presents observations on the spermatogenesis of 

 Syrhula (a grasshopper) and of Lycosa (a spider), together with- some 

 broader conclusions in regard to questions of the behavior of the 

 chromosomes during the maturation mitoses, and of the nature of those 

 modified nuclear elements which have been termed by me heterochro- 

 mosomes. 



The subject of heredity, which in its broadest sense includes most 

 of the problems of the phenomena of life, is being pursued from two 

 main lines: from that of the study of the germ cells, and from that of 

 an analysis of the results of cross breeding. The actual steps of the 

 process of heredity, if we shall ever understand them, will be learned 

 by the first method, by the investigation of the energies of those cells 

 which transmit ancestral traits. The second method is of less import- 

 ance than the first, for while it may permit an analysis of the propor- 

 tional transmission of different ancestral traits, it can in no way eluci- 

 date the steps of this process, for the very reason that its material 

 basis is the terminal stage alone, and the somatic condition at that. 



And of all cellular investigations, those that concern themselves 

 with the nuclear chromosomes seem to penetrate deepest into the mys- 

 teries of the problem, for these cellular components more than all others 

 seem proven to be the centres of hereditary energies; can we unlock 

 their secrets we will have opened the door to the light, for there seems 

 to be no other portal. 



The study of the chromosomes has ceased to be regarded as 

 an academic question, or as a mere side issue of problems of cell 

 division, and is slowly but surely coming into the centre of the field 

 of biological thought — of that thought which embraces the broader 

 community of natural phenomena and docs not lose sight of the forest 

 for the trees. All things are in the nature of processes, to the biologist 

 of genetic processes, and of the \dtal changes heredity is the one that is 

 the most comprehensive; broadly speaking, biology is the study of 

 heredity. There arc two methods used in the search for the solution, 



