118 bulletin: museum of comparative zoology. 



gonia staining like those of the apical cell. Griinberg (:03) has given 

 a detailed account of the apical cell in a number of Lepidoptera and 

 has come to the conclusion that it has two, more or less distinct, 

 functions. He agrees with La Valette St. George, in opposition to 

 Toyama, that it is a germ cell, but one which has become modified 

 for an entirely different function. In the embryo and young larva 

 the apical cell is closely applied to the testicular wall at the distal end 

 of the follicle. Later the cell enlarges and between it and the sur- 

 rounding spermatogonia can be seen a lighter area filled with cyto- 

 plasm containing numbers of deeply staining granules. He believes 

 this area to be formed by the disintegration of primary spermatogonia 

 which were directly in contact with the apical cell, and that the remains 

 of these cells, after being elaborated by the apical cell, serve as nutri- 

 ment for the remaining spermatogonia. Somewhat later the apical 

 cell moves into the lumen of the follicle, but for a time remains attached 

 to an ingrowth of the testicular wall. This connection with the outer 

 wall of the testis is probably retained to enable the cell to procure 

 nutritive material, which it elaborates for the use of the spermatogonia. 

 This view is supported by the fact that the cytoplasmic granules often 

 show a radiate arrangement, as though streaming out from the nu- 

 cleus to the surrounding spermatogonia. Griinberg (:03, p. 378) con- 

 cludes: "Ihre Thatigkeit als solche kann cine doppelte sein: durch 

 Aufnahme von Material und Verarbeitung desselben libt sie eine 

 assimilirende Thatigkeit aus; ausserdem kann sie durch selbstandige 

 Produktion von Nahrsubstanz die Bedeuttnig einer secer?i?'renr?c/i A?'a/ir- 

 zelle gewinnen." Recently Cholodkovsky (:05) has changed b.is former 

 view and accepts Griinbcrg's conclusions. 



In the Orthoptera the appearance of the apical cell suggests that it 

 has a similar function, although the e^^dence is far from conclusive. 

 It is possible that this cell is concerned in the formation of the mito- 

 chondrion, since this substance in the primary spermatogonia closely 

 resembles the finely granular material surrounding the nucleus of the 

 apical cell. In this connection it is interesting to note that the primary 

 spermatogonia, although dividing rapidly, are always of approximately 

 the same size, while the secondary spermatogonia rapidly decrease in 

 size in the later generations. 



2. The Spermatogonial Autosomes. 



It has long been known that there is often considerable variation 

 in the size of the different chromosomes in the 'same species, but it 



