IO HAROLD H. PLOUGH. 



haematoxylin, safranin and other chromatin stains. When the 

 Flemming triple combination is used the chromatoid body is red 

 throughout, even though the resting nuclei are purple. With 

 the Auerbach stain the body is clearly differentiated from the 

 chromatin, for it is bright red while the nuclei are green. With 

 the Benda alizarin-crystal violet method, even when the material 

 is fixed as directed with the modified Flemming's fluid, the 

 mitochondria seldom appear, and the nuclei and chromatoid body 

 appear bright purple. I have tried this method repeatedly with 

 the germ cells of Rhomaleum but have never been able to get the 

 brilliant result shown by Giglio-Tos and Granata (1908) in their 

 paper on Pamphagus marmoratus. With the Altmann acid 

 fuchsin method the chromatoid body is clear red as are the 

 mitochondria. The material is therefore unlike either mito- 



I 



chondria or chromatin in chemical constitution, a fact clearly 

 shown by its behavior. 



I am glad of an opportunity to express my indebtedness to 

 Professor E. B. Wilson for generous advice in the preparation 

 of this paper as well as for numerous suggestions with regard to 

 technical methods. I am also indebted to Miss Mabel Hedge 

 for the original drawings of Figs. 3 and 4. 



SUMMARY. 



The mitochondria in Rhomaleum are shown to be present In 

 the spermatogonia. Their behavior agrees closely with that 

 described by Lewis and Robertson for Chorthippus, except that 

 they remain granular throughout. 



There are present in the spermatogonial cells of Rhomaleum in 

 addition to the mitochondria certain fine granules which stain 

 in contrast to the mitochondria with neutral red. These granules 

 are carried over into the early spermatocytes where they prob- 

 ably become aggregated into one mass. This mass grows for 

 a short period, passes inert through the two maturation divisions, 

 and into one fourth of the spermatids. From the tails of the 

 developing sperm it is cast off into the end of the follicle, where 

 it degenerates. In addition it has been noted that an idiozome 

 or attraction sphere is present in the early spermatocytes of Rhoma- 

 leum, and an acrosome sphere in the spermatids. 



COLUMBIA UNIVERSITY, 

 October 5, 1916. 



