104 PROCEEDINGS OF THE AMERICAN ACADEMY. 



In the final generation of spermatogonia in the honey bee there is at 

 the apex of each conical cell a spheroidal, nearly homogeneous body, 

 which represents the remnants of the interzonal filaments of the pre- 

 ceding cell division. These bodies are stained black in iron haema- 

 toxylin, and on being washed out assume a characteristic yellowish 

 gray color. Since they are admittedly the metamorphosed remnants 

 of filamentous structures first named by Mark ('81, pp. 198, 539) inter- 

 zonal filaments, we shall henceforth speak of them as the Interzonal 

 bodies. The interzonal body is identical with the " Zellkoppel " of Paul- 

 mier ('99, p. 228), to which Prowazek (:01, p. 201) has given the name 

 " Spindelrestkorper." It is to be noted that the term " Zellkoppel " 

 was used by Zimmermann ('91, p. 189), who introduced the name 

 into cytology, with a somewhat diiferent meaning from that employed 

 by Paulmier. This is in itself a reason for applying another name — 

 interzonal body — to this structure. 



At the end of the growth period, which follows the last spermato- 

 gonial division, the cells have increased greatly in size and have be- 

 come in general spherical, a form which is more or less modified by 

 the mutual pressure of the closely packed elements. At this stage 

 (Figure 1) the interzonal body {x) is clearly visible, and is in contact 

 with the cell membrane. Meves shows it in his Figure 1, but makes 

 mention of it neither in his explanation of the figure nor in the accom- 

 panying text. 



The first evidence of spermatocyte division is seen when the centro- 

 some, which lies in contact with the cell membrane, divides and the two 

 daughter centrosomes move apart along the periphery of the cell. The 

 centrosomes during their migration appear to exert a marked influence 

 on the form of the cell, which exhibits two more or less conspicuous 

 elevations, the apex in each case being occupied by one of the centro- 

 somes. Figure 2 represents a fairly early stage in the migration of the 

 centrosomes and shows clearly the marked change in the form of the 

 cell due to their presence. The distance between the two centrosomes 

 increases until these ultimately arrive at opposite poles of the cell 

 (Figure 3). Up to this time each centrosome seems to have exer- 

 cised nearly the same amount of influence as the other in modifying 

 the form of the cell ; but from this time forward the influence of one is 

 seen to predominate over that of the other, until at length (Figure 4) 

 one end of the cell is drawn out into a long, slender, slightly tapering, 

 finger-like process, at the tip of which is located the centrosome. 

 This centrosome will be designated as the proximal one, the other as 

 the distal centrosome. 



The choice of these designations rests on a later condition in the 



