220 Nichols, A morphological study of Juniperus communis var. depressa. 
gone division (fig. 67). In two of the cells figured, one of the 
daughter nuclei of the first division kas redivided, wkile in the 
other tke heterotypic division kas just been completed. Wketker 
more tkan one of tke functional megaspores tkus formed would 
kave developed furtker cannot, of course, be stated, but it is not 
unlikely, since Sludsky (1905) reports tkat in tke European form 
ke twice found two endosperms in a single nucellus. In connection 
witk tkese abnormal cases it is interesting to note tkat here, as 
in Ory'ptomeria (Lawson 1904b), two megasporangia occasionally 
occur witkin a single integument. 
Düring tke division of tke megaspore motker cell tkere is 
present just below tke nucleus tke conspicuous kinoplasmic body 
(figs. 63, 66, 67) wkick Noren (1907) kas described in tke European 
form. Analogous strnctures kave been noted in tke megaspore 
motker cells of Taxoclium, Thuja, and Taxus (Coker 1903, 1904), 
and Torreya (Robertson 1904a). Its significance is still a matter 
for discussion, but it may be wortky of mention tkat tke writer 
kas observed very similar bodies in tke later stages of protkallial 
development (fig. 77). 
Immediately following tke komotypic division tke functional 
megaspore becomes cut off by a membrane and enlarges until it 
fills tke entire space originally occupied by tke motker cell (figs. 
68, 69), wkile tke nuclei of tke non-functional cells rapidly dis- 
organize and are. eventually absorbed. 
The female gametophyte. 
Development of tke protkallium. — Tke observations 
of Noren (1907) on tke development of tke female gametophyte, 
briefly stated, are as follows: Tke megaspore germinates rapidly 
and gives rise to an embryo sac containing a large central vacuole 
and numerous free nuclei imbedded in a peripkeral layer of cyto- 
plasm. Nuclear division takes place simultaneonsly througkont tke 
sac. In tke development of tke protkallium open tubes are formed 
wkick grow in toward tke center of tke embryo sac in tke 
manner first described . by Mlle. Sokolowa (1890). The nucleus 
of eack tube tken divides, and cross walls are laid down. Tke 
megaspore membrane consists of two distinct layers. Noren’s 
observations are for tke most part confirmed by tkose of tke 
writer. 
Tke development of tke embryo sac from megaspore to multi¬ 
cellular protkallium occupies about five weeks. Düring tke few days 
following its differentiation tke megaspore increases very little in 
size, but tke primary nucleus undergoes its first division. 
Tke two resultant nuclei occupy a central position, and tke cell 
contains several small vacuoles. With tke advent of tke four 
nucleate stage tke small vacuoles flow togetker to form one large 
central vacuole, and tke cytoplasm witk its included nuclei comes 
