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ATLAS DEUTSCHER MEERESALGEN. 61
which Dr. Keinke is known to be a special authority. As a rule
every species is illustrated by a life-size drawing, and by a series
of microscopic figures, under various powers, showing every part
of the structure, and, so far as is possible, all stages of development.
The figures are remarkable for their minute accuracy,
and it will be noticed that special attention is paid to the form
and distribution of the chromatophores. An English botanist on
looking at these plates may well feel envious, and wish that our own
far richer algal flora could be illustrated in the same thoroughly
scientific manner. Let us trust that this wish will eventually
bring about its own realization.
We will notice a few of the more important forms specially.
Halothrix is a new genus founded by Dr. Reinke, for the species
H. lumbricalis (pi. 1), placed by Kiitzing in Ectocarpus, and transferred
by Hauck to Elachista. The genus comes very near
Giraudia, but the upright assimilating filaments are usually
monosiphonous. Only plurilocular sporangia are known, which
are developed in sori on the upper parts of these filaments. The
central portion of the mother-cell of each sorus divides up to a
certain extent, but remains sterile.
The next genus, Symphoricoccus, is founded on a species S. radians,
discovered by Dr. Eeinke. It is closely related to Elachista, but
differs from that genus in the fact that the unilocular sporangia
(here the only kind known) occur on the upper part, as well as at
the base of the assimilating filaments. It is interesting to note
that here a small cell is cut off at the base of each sporangium; this
cell grows out into the cavity of the old sporangium when it is
empty, forming a new one to rej^lace it. Much the same process
has long been known to occur in Cladostephus.
Kjellmannia Eke. is an interesting genus placed by its author in
the group Punctarieas. The branched polysiphonous thallus bears
short monosiphonous branches. There are two kinds of sporangia,
both plurilocular, one kind intercalary, the other in -sori. Like its
near relations this genus has no definite growing point, the
intercalary growth going on indiscriminately in all regions.
Passing over some forms of Asperococcus and Ralfsia, of less
general interest, we come to Microspongium gelatinosum Rke.
(Pis. 7 and 8.) This is the type of a new genus of MyrionemeaB,
coming next to Asconjclus Magn. There is a basal disc, two cells
thick, with marginal growth. From this arise vertical hairs and
assimilating filaments. The latter have a chiefly apical growth,
a fact which shows how little importance can be attached to this
character among the Phoeosporea). Plurilocular and uuilocuhir
sporangia are formed on distinct plants, but it is not absolutely
certain that these forms are specifically identical.
In plates 9 and 10, three varieties of Lcplonema fasciculatmn.
Rke. are figured. Leptonenm is a new Elachistcous genus, placed next
Halothrix. Fiom a creeping protoncma arise assimilating filaments
only branched at the base. Growth is intercalary and
basipctal as in the group generally. Botli kinds of sporangia
occur. The unilocular sporangia arise laterally, close to the base