402 BOTANICAL GAZETTE [DECEMBER 
cytological evidence for this view. Wotre (86) placed this theory 
of OLTMANNS on a cytological basis by showing that the cystocarp 
of Nemalion contained nuclei with double the number of chromosomes 
found in the sexual plants or gametophytes. However, WoLre did 
not give a detailed account of the period of chromosome reduction. 
Nemalion is one of the simplest types of the red algae. ‘There are no 
auxiliary cells or tetraspores, at least on the American plants so far 
as known; consequently the life history is very much simpler than 
that of the higher forms. The behavior of the auxiliary cell nucleus 
during the development of the cystocarp has been studied by OLt- 
MANNS (55) with especial clearness in Callithamnion and Dudresnaya, 
but the structural difference between the nuclei of auxiliary cells 
(gametophytic) and those derived from the fertilized carpogonium 
(sporophytic) was not determined by him. Moreover, as regards the 
real nature of the tetraspore, so characteristic of the red algae, there 
has been no cytological work except a study of nuclear division in 
Corallina by Davis (18). 
The significance of the tetraspore in the life history was not 
known. Various authors have presented speculations upon the 
subject; for example, OLTMANNS (55) regarded the tetraspore as 
an asexual reproductive structure comparable to brood organs or 
gemmae, having no fixed place in the life cycle, and STRASBURGER 
has followed this interpretation. 
This investigation was begun in the hope that some of these problems 
might be solved by carefully following the life history of a type with 
particular attention to the behavior of the nucleus at critical periods. 
Although red algae include a wide range of types, the nature of the 
tetraspore and the history of the life cycle where tetraspores are present 
have probably been determined by this investigation of the ontogeny. 
of Polysiphonia violacea Grev., except in forms where abnormalities 
may be present, due perhaps to apogamy or apospory. 
As stated in a preliminary paper (YAMANoUCHI 87), the material 
was collected at Woods Hole, Mass., during July and August 1995, 
where cultures of the carpospores and tetraspores were made to 
obtain stages in their germination. The method of killing, fixing, 
imbedding, cutting, and staining are given in that preliminary note. 
This paper presents first the results of my studies of the mitosis in 
