OOGENESIS AND EARLY EMBRYOLOGY ASCARIS 541 



undergoes further condensation, gathering toward one side of 

 the peripheral mesh work, leaving behind a fine linin net free 

 from chromatin. This stage corresponds very closely to the 

 'bouquet' stage which Marcus ('06) describes for his dog ascaris. 

 Hertwig ('90), Tretjakoff ('04 a), Griggs ('06), Gregoire ('10), 

 Bonnevie ('12), and Vejdovsky ('12) mention similar stages in 

 A. megalocephala. Saedeleer ('12), however, does not find in 

 this species any such stage. A condition similar to the 'bou- 

 quet' has been seen by Kiihtz ('13) in a species of Sclerostomum 

 from the horse. 



It is during this stage that synmixis takes place, if it takes 

 place at all, for every chromosome has lost its morphological 

 identity in the common mass, and there is nothing to prove that 

 the chromosomes arising from this mass are absolutely identical 

 with the ones which enter into it. 



The cytoplasm of the cell has undergone rapid growth, espe- 

 cially along its radial axis, and the cell has thus become shaped 

 like a pear or a truncated cone, with the small end toward the 

 rhachis. This change of shape is coexistent with an absorption 

 of the lamellae and an increased linear growth of the rhachis- 

 This allows all the cells to lie at the same level, their small ends 

 touching the rhachis, or attached to it, and their large ends 

 reaching the periphery of the oviduct. These cells have a some- 

 what less angular outline than heretofore, due to less crowded 

 conditions in the oviduct. The nucleus is situated in the larger, 

 peripheral end of each of the oocytes (fig. 13). 



The cytoplasm has become more definitely reticulated, the 

 granules seemingly being arranged in thread-like chains. At the 

 outer end of the cells a few vacuoles begin to form (fig. 13), 

 some of which are already fairly large. These increase very 

 rapidly in number as the cell matures (fig. 15). 



The nucleus (fig. 13) during these cytoplasmic changes has 

 undergone still further condensation of the chromatin of the 

 'bouquet,' which becomes definitely one body, slightly irregular 

 in outline, and having a few, rapidly disappearing linin threads 

 diverging from its periphery (fig. 15). In many cells the lin n 

 network has entirely disappeared (fig. 16). These radiating 



