PROGRESS OF MICROSCOPICAL SCIENCE. 305 
several species placed by De Koninck under Cyprella, Cypridella, and 
Cypridina,—and a more exact interpretation of M‘Coy’s Entomoconchus, 
are (besides many new species) the chief novelties of this memoir, 
which is illustrated by five plates (by George West) very full of 
excellent figures of these small fossils.” 
Reproduction of Ulothrix zonata.—In a series of most valuable 
abstracts of German botanical papers that Mr. 8. Le M. Moore is 
giving in the ‘ Journal of Botany’ (May), appears the following, which 
is taken from a paper by Dr. Arnold Dodel in ‘ Pringsheim’s Jahr- 
bucher fiir Wissenschaft. Botanik’ (vol. x. p.417):—Ulothrix zonata has 
spores of two kinds—viz. 4-ciliated macrozoospores produced either 
singly or two together in the mother-cell, and 2-ciliated microzoo- 
spores arising several together in each mother-cell. Sometimes the 
two spore-forms are found in neighbouring cells of a thread, but they 
usually have distinct periods of activity, autumn and winter being 
favourable to the formation of macrozoospores, and spring and summer 
to that of microzoospores. The latter copulate and form resting zygo- 
zoospores, a fact which sets Areschoug’s position beyond cavil; but 
the strangest thing of all is that those individuals which fail to 
copulate are like the macrozoospores in having the power of imme- 
diate asexual reproduction. This most remarkable observation, which 
its discoverer regards as furnishing a transition state between sexual 
and asexual generation, comes to some extent to the timely support of 
the Strassburg school, who deny that the fact of germination is suffi- 
cient proof of the asexuality of spermatia. Several figures are given 
showing polymorphism of the threads and of the zoospores; between 
the two forms of the latter there are all kinds of transition, the only 
absolute distinction being based on the number of cilia. Further, it 
has long been known that microzoospores sometimes germinate while 
still in the mother-cell, and Dr. Dodel has seen some of them dege- 
nerate in this position without budding. Dr. Dodel agrees with 
Pringsheim that copulation of microzoospores is the morphological 
type of sexual reproduction. As for the zygozoospore, which, germi- 
nating after its period of rest, produces, not a thread of cells but a 
variable number of zoospores from which the threads arise, it is 
regarded as an independent new sexual generation, so that we have in 
Ulothriz true alternation of generation. Dr. Dodel points out the 
affinity of Ulothrichee to Volvocinee and Hydrodictyee, but he is too 
prudent to dogmatize on the subject of classification. He holds, 
however, that the facts he has discovered afford strong support to the 
theory of evolution, as they show how (morphologically, of course) an 
asexual cell may become endowed with sexual properties. 
MicroscopicAL Contents oF ForEIGN JOURNALS. 
Archiv fiir Mikroskopische Anatomie, 13 Band, 4 Heft (continued 
from last number of ‘M. M. J.’)—On the Cell-formation which 
occurs in the Connective Tissue of Muscles, by Walther Flemming, 
This is a paper illustrated by three very good plates. It treats 
