2 37 
Algal Ancestry of the Higher Platits. 
have some biological significance that has as yet escaped recognition, 
but in any case we must regard them as a special development, 
which may not interfere with our perspective in estimating the 
remaining morphological characters of this group. 
Fig. 1. a, Myxonema tenue, habit (after Huber) ; b. M. favctum, small portion 
of the creeping base (after Berthold) ; e, M. prostration, a portion of the base ; 
d. Protoderma viride (after West); c, Aphanocluete repens (after West), only the 
bases of the hairs are shown ; /, Trentepohlia umbrina, end of an upright thread 
with three zoosporangia (after Oltmanns) ; g, T. aitrea, base and erect system, 
the former with three gametangia (after Brand) ; h, T, ellipsicarpa, Schmidle, 
var. africana, Schmidle (after Schmidle). 
The height of morphological differentiation among the Chseto- 
phorales, in fact among the filamentous Isokontae generally, is 
attained by the genus Draparnaldia, a fact first brought out clearly 
by Berthold. 1 The elaboration in this case concerns the upright 
system, and, in correspondence with this, the creeping base is 
poorly developed ; in some cases, according to Berthold, it is com- 
1 Berthold, loc . cit., p. 202 et seq. 
