22 DUBLIN 



tant, because from the works of several authors, it would ap- 

 pear that there was such a connection, and that the granules 

 first formed and divided each longitudinally to form the beaded 

 sister-arms. 



The chromosomes have taken part in the growth so char- 

 acteristic of both cytoplasm and nucleus. As in Canthocamptus 

 and the Copepods generally, there is no period of rest nor is 

 there a true chromatin-reticulum formed. The individual chro- 

 mosomes persist as such from the last oogonial telophase, 

 through the growth period of the oocyte into the maturation- 

 spindle, where they become the tetrads and rings to be described 

 later. Nor is there at any stage during the ^gg growth, a con- 

 tinuous spireme. In this regard Pedicellina is unlike such forms 

 as the Copepods and some other Crustacea, and resembles the 

 spermatocytes of Peripatus, Brachystola (Sutton), and Anasa 

 (Paulmier, '99). There is, therefore, no possibility of the for- 

 mation of the bivalent chromosomes by the transverse division 

 of a continuous chromatin thread, as has been described in the 

 former of the above groups. The formation of a continuous 

 spireme appears even in these forms to be but a secondary 

 process, w^hich may or may not occur, and as Hacker, '97, 

 points out, there is even in the same species a great amount of 

 variation in the time of its segmentation. 



The cytoplasm has by this time increased in amount, and the 

 cells now have the characteristic appearance of oocytes (Fig. 

 "Jj). The chromosomes show no order in their distribution, 

 and cross and intertwine among themselves. They have also 

 become extremely granular and ragged at this point, and in 

 some cases show distinct breaks in their course, making it often 

 difficult to follow the individual bivalents throughout. It is 

 then that the linin-reticulum in which the chromosomes are sus- 

 pended is most clearly visible. This new element has now 

 become of considerable importance. In the early stages of 

 growth there was next to nothing of the reticulum to be seen. 

 As the nucleus grows, it comes more and more into view, until 

 finally it appears much like a web, crossing the nucleus at all 

 points and serving as a support for the chromosome. With 



