4 66 Fraser and Weis ford. — Further Contributions to the 
we believe, a disused ascogonium (PL XXVI, Fig. i). The hypothecium is 
pseudo-parenchymatous, and consists of polygonal, closely placed cells ; 
this arrangement differs from that in H. rutilans where the ramifications 
of individual hyphae can be distinctly traced. The hypothecial nuclei are 
too minute for satisfactory investigation, and consequently the attempt was 
early abandoned to observe the first and presumably pseudapogamous fusion. 
In the sub-hymenial layer the ascogenous hyphae are distinguished by 
their dense contents. The nuclei are vacuolate, and, though larger than 
those of the hypothecium, they are still difficult to study. We found no 
indication of a conjugate arrangement. 
In O tide a aurantia , Mass., as in H . rutilans , the first divisions in the 
ascus constitute a meiotic phase, and here also they correspond closely to the 
description given by Farmer and Moore ( 9 ). The various stages are almost 
diagrammatic in clearness (Figs. 2-10), and we feel no doubt as to their 
significance. 
After the first contraction (Fig. 2) the spireme splits longitudinally 
(Fig. 3), synapsis takes place (Fig. 4), and four loops are formed (Fig. 5) ; 
in the limbs of these the longitudinal fission is seen, and they break apart 
to form the four gemini (Moore and Embleton (21)) or bivalent chromo- 
somes (Fig. 6) which undergo considerable contraction. A transverse 
fission takes place on the heterotype spindle (Fig. 8), and the longitudinal 
fission is completed on that of the homotype (Figs. 11, 12). Four chromo- 
somes thus travel to each pole both in the first (Fig. 9) and in the second 
mitosis (Figs. 12, 13). 
During the early stages of meiosis the fusion in the ascus takes place. 
The third division is inaugurated by a contraction 1 of the chromatin 
thread (Fig. 14) and two or sometimes four chromatin masses become 
visible (Figs. 15, 16). The spindle is then formed and in the early 
metaphase two long chromosomes are observed (Fig. 17). The exact 
sequence of the prophases is difficult to determine, but it seems clear that 
the two chromosomes of the metaphase are bivalent and that each represents 
two of those which pass to the poles in the previous mitosis. On the spindle 
they divide, and two small daughter-chromosomes travel to each pole. 
This division appears, like the corresponding one in H. rutilans , to be 
brachy meiotic in character and to result in the separation of different 
portions of the nuclear thread. 
During all three divisions in the ascus one or two granules are 
frequently seen within the nuclear area (Figs. 8, 13, 17). They may be 
connected with the centrosome by ‘ fibres ’ resembling those of the spindle 
1 Contraction is sometimes seen in the daughter nuclei after the first mitosis, the chromatin forming 
a dense mass at the end of the nucleus remote from the plane of division. This differs from the 
contraction of a chromatin thread observed in the third mitosis here and in both divisions in 
P. vesiculosa ; it probably represents a stage of reconstruction comparable to Fig. 32. 
