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HARGITT: PENNARIA TIARELLA AND TUBULARIA CROCEA. 195 
In Tubularia crocea the odgonia are all alike; but in the odcytes, 
even before growth begins, a difference is apparent, the chromatin in 
the nucleus being either (1) in the form of a spireme or (2) scattered 
in grains along a network. ‘The odcytes which possess a nuclear 
spireme begin growth at once, the most of those with a diffuse net- 
work serve as food, though if they escape this fate they seem to be able 
later to form egg cells. ‘The cause of this differentiation seems to be 
better nourishment, as the odcytes near the spadix are most often the 
ones which first begin to grow. (Fon 
The cell which begins to grow absorbs the surrounding cells by one 
or another of various methods... The nucleus of this growing odcyte 
is commonly believed to become the germinative vesicle, while the 
nuclei of the absorbed cells are used as food at once, or remain in the 
cytoplasm as yolk bodies, ‘‘pseudo-cells.”’” However, Allen (:00, p. 
300) says in regard to Tubularia (Parypha) crocea: “....the nuclei 
of the growing cells disappear at an. early stage, so that only the 
nuclei of the smaller cells persist.’’ “It thus becomes impossible to 
tell which is the controlling cell.’ This is exactly the opposite of 
what I find in the same species, for in my preparations the nucleus 
of the growing oécyte is always present and easily distinguished, 
because of marked differences between it and the degenerating nuclei 
of the absorbed odécytes. ; 
2. Synapsis and Reduction.— In 'Tubularia after the last odgonial 
division, and before the growth of the primary odcyte begins, the 
chromatin of the nucleus is in the form of a spireme, which soon takes 
the form of loops showing a definite polarity, the open ends of the 
loops apparently being attached to the nuclear membrane. ‘This 
condition seems to correspond to similar polar arrangements of the 
spireme in the synapsis stage of other metazoa. A synapsis in Coelen- 
terata has been described in spermatogenesis by Guenther (:04) and 
Downing (:05) for Hydra, and by Bigelow (:07) for Gonionemus. 
Stschelkanowzew (:06) figures nuclei of spermatocytes in which the 
chromatin appears to be in a contraction stage or polar arrangement, 
but does not so describe it. ‘The characteristic condition is such as 
might result from a contraction into a dense mass. Bigelow thinks 
that in Gonionemus this is artificial. ‘Trinci (:07) has described a. 
synapsis as occurring during the odgenesis of several Hydromedusae. 
He also shows a contraction phase, though in his figures the chromo- 
somes still show a rather definite polarity after the contraction. 
After the contraction Guenther found a reduced number of chromo- 
somes, while Downing thinks the reduction occurs in the telophase of 
