104 Church. — The Polymorphy of 
Z ancirdinia which will not only include the existing data, but 
may present some suggestions towards the solution of other 
algological problems. 
The evolutionary specialization of the Cutleriaceae, with 
which we are here concerned, takes into account the vegetative 
structure only. A comparison of Cutleria multifida (including 
Aglaozonia reptans ), Cutleria adspersa (and its suggested 
Aglaozonia c kilos a), and Z anardinia collaris shows that in 
the structure of the reproductive organs the three types are 
identical. In both genera the asexual sporangia give rise 
to a few (6-1 o) large biciliated zoospores, and thus present 
an intermediate reduction-specialization as opposed, on the 
one hand, to the numerous spores from the unilocular sporan- 
gium of Ectocarpus siliculosus , &c., and to the immotile 
monospore of the Tilopterideae on the other. 
The antheridia show a slight advance on the primitive 
Ectocarpoid multilocular sporangium, in the more complete 
delimitation of the antherozoid-tissue, best seen in the skeleton 
framework remaining after emission of the antherozoids, but 
they have not attained such a high degree of specialization 
as that exhibited by the bottle-like antheridium of the 
Tilopterideae. 
In the same manner, a further degree of reproductive con- 
centration has, in correlation with the increase in bulk of the 
female gametes, reduced the segmentation of a multilocular 
gametangium to an oogonium of sixteen loculi, each producing 
a single oosphere ; but this again is a lesser degree of reduc- 
tion than that obtaining in the Tilopterideae with huge solitary 
oosphere. 
Hence, in all three forms of reproductive organ, the Cutleri- 
aceae offer a condition intermediate between the isogamous 
Ectocarpaceae and the completely heterogamous Tilopterideae ; 
and they may, in view of the present vegetative condition of 
these two groups, be regarded as descended from a filamentous 
form which had attained the present comparatively high 
degree of sexual differentiation before passing beyond the 
branched filamentous condition in its vegetative structure. 
