228 Barker . — The Morphology and Development of 
important connecting link between the Oomycetes and Asco- 
mycetes. 
Holtermann (13) has described a form, Conidiascus , which 
he places among the Hemiasci, in which reproductive bodies 
are produced as conidia like those of Peronospora , which later 
produce a few spores by the division of their contents, epiplasm 
being formed during the division. This form of reproduction 
is regarded as intermediate between conidia and asci, and 
thus serves to connect zoosporangia, which are homologous 
in the Peronosporaceae with conidia, and asci. The processes 
leading up to the formation of these structures do not seem 
to be thoroughly known at present, so that the comparison 
cannot be extended here. 
Popta (17) has shown that the method of spore-formation 
in Ascoidea is more nearly allied to the Ascomycetous type 
than to that of the Phycomycetes, owing to the occurrence of 
periplasm. The sporangia are apparently produced asexually. 
Harper (11) believes that Popta's results either indicate a 
method of division similar to that which he has described for 
Pilobolus , or that the process is unique and differs from that 
occurring in the sporangia or asci studied up to that time. 
Having reviewed briefly some of the features which seem 
to be of most importance in the question of relationship, there 
remain a few points which may be further considered. It has 
been seen that the antheridia and oogonia of the Oomycetes 
have probably been evolved from gametangia, the separate 
motile gametes of which have lost their individuality, and in 
the simplest forms such as Albugo Bliti , while several remain 
functional, others have lost their sexuality, or rather remain 
unfertilized, and constitute the periplasm, which may be 
supposed to have thus originated. Other forms, such as 
Peronospora parasitica , show a higher degree of differentiation, 
only one male and one female gamete remaining functional. 
Similarly, among the Ascomycetes, which still possess an archi- 
carp of functional male and female organs, Monascus and 
Pyronema behave like Albugo Bliti , and Sphaerotheca — and 
Dipodascus among the Hemiasci — like Peronospora parasitica. 
