Among the numerous changes of opinion recorded by Montgomery in his latest work, there are several relating to his “chromatin nucleolus” that materially alter the aspect of the question. Perhaps the most important of these concerns the origin of the element. I was some time in determining that the accessory chromosome is a spermatogonial chromosome which divides in the spermatogonia with the other chromatin elements and comes over into the first spermatocyte as a formed structure. The work of Sutton upon the early history of the element in _Brachystola_, however, was convincing in this respect and confirmed me in the opinion I had already formed. I therefore gave Montgomery the credit for this discovery, and set it down as strong confirmation of the assumption that we were dealing with similar structures in the two orders of insects. Upon this point Montgomery now completely reverses himself, and declares that his “chromatin nucleolus” is not a spermatogonial chromosome, but may be noted in the earlier generations as a nucleolar structure, which, however, divides in metakinesis. The most important feature to be noted in this connection is the fact that the structure does not exist as a simple element, but is observed as a number of granules, and that this number varies considerably in different species. These granules fuse during the “synapsis stage,” as do the chromosomes, to produce in the spermatocyte half the number of “chromatin nucleoli” that were present in the spermatogonia. In this respect the “chromatin nucleolus” differs radically from the accessory chromosome, which has the same valence in both cell generations. The indefinite number and insignificant size of Montgomery’s structures are other characters that point to extensive differences between them and the accessory chromosome. In his work upon _Peripatus_, Montgomery states that in restudying his preparations of _Euchistus_ he observes a continuous linin spireme which involves the “chromatin nucleolus” as well as the chromosomes. Here, again, there is a difference between the Hemipteran element and the accessory chromosome; for the latter is entirely free from linin connections in the prophase and is usually surrounded by a hyaloplasmic investment. According to Montgomery, also, his “chromatin nucleolus” usually takes part in both spermatocyte mitoses. In this respect there exists an essential difference between his element and that found in the Orthoptera, for, after extended and most critical studies, I have become convinced that only one division takes place in the spermatocytes. In those cases where Montgomery admits but a single division, it is stated to occur in the first spermatocyte, while in the Orthoptera the accessory chromosome remains undivided here and is halved in the second spermatocyte.