389 
Tavel, F. yon. — Vergleichende Morphologic der Pilze. Jena, 1892, 8vo, 
pp. 11, 208, figs. 90. 
This book puts the whole Brefeldian system into such, a compact and 
lucid form that he who runs may read. The revolutionary work done 
by Dr. Brefeld and Ids assistants during the last twenty years in every 
group of fungi and embodied in ten large u Heften,” with more to fol¬ 
low, is here condensed into less than 225 pages, and yet completeness 
and perspicuity of expression, so far as regards essential features, are 
everywhere apparent. That Dr. von Tavel is well fitted for this task 
goes without saying, since he was Dr. Brefeld’s assistant for a number 
of years, and is joint author with him of Heften rx and x on Hemiasci 
and Ascomycetes. 
According to the views here set forth, fungi consist of two primary 
groups: (1) The Phycomycetes, or algal fungi, consisting of a single 
cell and having sexual functions; and (2) theMesomycetes and Mycomy- 
cetes, or higher fungi, consisting of a many-celled thallus and entirely 
destitute of sexual organs. The Phycomycetes have a thallus resem¬ 
bling that of the Siphoneae and were undoubtedly derived from the algae. 
They subdivide naturally into two quite distinct groups, the Oomycetes 
and Zygomycetes. The Oomycetes resemble the Oophyceae both in the 
thallus and in the reproductive system. In each group the organism 
consists of a nonseptate, sparingly branched cell, which reproduces sexu¬ 
ally by antheridia and oogonia, and nonsexually by swarm spores devel¬ 
oped in sporangia. But the Oomycetes show degenerations and retro¬ 
gressions which appear to be adaptations to a more terrestrial life. 
Especially noteworthy is the progressive loss of sexuality. 
The group is divided into six families, including Entomophthoree, 
which stands midway between Oomycetes and Zygomycetes, having 
reduced antheridia and oogonia which conjugate, and an abundant coni- 
dial fructification. Beginnings of conidial fructification also appear in 
some of the other families. In Zygomycetes the thallus is one-celled and 
agrees completely with that of the Oomycetes, but the fructification is 
different. In this group there is still further degeneracy in the sexual 
reproduction. Instead of the union of specialized sporangia (antheridia 
and oogonia) to produce the zygospore, there is simply a conjugation of the 
slightly differentiated beginnings of such sporangia, i. e., the conjugat¬ 
ing threads are only slightly swollen and the male and female organs can 
not be distinguished. Nonsexual sporangia are present as in Oomycetes, 
but the spores have lost their cilia with the more decided adaptation of 
thesepdants to a dry-land life. In the possession of a one-celled thallus 
the Zygomycetes are also like the alge, and they resemble the Conju¬ 
gate in conjugation, but not otherwise. The first five families are 
exosporangic, producing sporophores anywhere on the mycelium; the 
other two, Rhizopie and Mortierellacee, have progressed a step fur¬ 
ther and ape earpo-sporangic, bearing their sporophores on specially 
