THE EMBRYOLOGY OF THE HONEY BEE 233 



only here and there. However when the head fold 23 is formed, 

 a multitude of these cells appear in the yolk, which are agglomer- 

 ated to the number of 8, 9 or even more in a single mass ; some 

 of these nuclei are now like the double nuclei described above, 

 although not so clearly divided into two halves. At this time I 

 could no longer discover the double nucleated cells. Could those 

 (just described) have arisen from these?" It seems highly 

 probable that the imperfectly double nuclei just described are the 

 small mitotic figures ; the resemblance of these which are found in 

 the true yolk cells to those seen in the "Richtungsplasma" is espe- 

 cially interesting. 



During the period of irregular mitotic divisions of the yolk 

 cells small and densely stained bodies appearing to be composed 

 of nuclear material (chromatin) are found within the cytoplasm 

 of the yolk cells (Fig. 93G, upper left hand side). The precise 

 origin of these bodies is unknown, but it seems that like the 

 similar bodies seen later, they represent degenerating nuclei, and 

 are also probably in some way causally related to the irregular 

 mitotic divisions. 



In preparations of eggs eighteen to twenty hours old, when the 

 nuclei of the blastoderm are arranged in a double layer over the 

 greater part of the blastoderm, the cellular contents of the yolk will 

 be found to present a richly varied appearance, and one which 

 differs not a little in different eggs ; nevertheless the following 

 description will apply to the majority of examples of this stage. 

 Scattered throughout the yolk are to be seen numerous irregular 

 islands of dark-staining cytoplasm of the most various shapes 

 and sizes containing one to several nuclei. These cells — or syn- 

 citia, since they are nearly all multinucleate — are most numerous 

 along the central line of the yolk, and are also rather more numer- 

 ous in the anterior than in the posterior half of the egg, although 

 syncitia of considerable size are frequently to be seen lying in 

 contact with the inner surface of the blastoderm. The range 

 in size of the syncitia may be gathered by comparing figures 

 92A and 92C. In the anterior half of the egg, always near the 

 central line of the yolk, there are usually one or two syncitia of 



23 Reference to the figures shows that by this is meant only the dorsal 

 strip of thin blastoderm. 



