112 MARGARET REED LEWIS AND WM. REES B. ROBERTSON. 



elongates the granules form two irregular granular strands, which 

 later fuse into two continuous threads of even width extending 

 from the centrosome body or middle piece to almost the end of 

 the tail (Figs. 49, 50 and 51). 



Duesberg ('10) describes a small body composed of mito- 

 chondria at the tip of the head, but in this form such a body was 

 not seen either in the living spermatozoon or in those stained with 

 Janus green. 



Unfortunately it was impossible to study this material in all 

 its details during the short time at Woods Hole and there are 

 many interesting points to be followed out, which it is hoped may 

 be continued in later studies upon another species of grasshopper 

 by Robertson. 



DISCUSSION. 



The above observations show that there are present in the male 

 germ cell from its earliest appearance throughout its develop- 

 ment certain granules which correspond to the mitochondria of 

 somatic cells. The mitochondria behave in a definite and char- 

 acteristic manner during the development of the male germ cell 

 and assume a shape and position characteristic for each stage in 

 the development. The mitochondria of the germ cell become 

 slightly blackened with osmic acid, are destroyed by acetic acid 

 and stained by Janus green and the usual stains for mitochondria 

 in fixed material. That they are not the remains of spindle 

 fibers has been clearly shown by means of acetic acid, which 

 destroys the mitochondria and causes the spindle fibers to appear. 

 On the other hand it does not seem possible that bodies, which 

 have to do only with the metabolic activities of the cell should 

 necessarily undergo such an exact behavior as is shown for in- 

 stance by the division of the nebenkern into equal parts and the 

 development of these two sacs of mitochondria into the two long 

 threads of mitochondria in the spermatozoon. Neither does the 

 behavior of the mitochondria seem to be entirely dependent on 

 changes within the cell, as for instance during the division of the 

 cell or the growth of the tail, where it might appear that the elon- 

 gation, and at the same time narrowing of the tail, might force 

 the mitochondria granules to assume the position of two contin- 

 uous threads, for in some cases where the tail does not develop 



