Neomeris dumetosa, L amour. 597 
a correlation would be further supported by the discovery 
by Solms 1 and Cramer 2 that these each possess in the young 
condition e solitary dichotomously branched hairs 3 placed 
laterally. The peculiar aberrant form may be regarded as 
a further development of the tendency to bulge on the basi- 
scopic side. The most remarkable feature, however, in 
Halicoryne Wrightii is the late formation in the fertile 
segments of a new septum delimiting the reproductive ‘pod ’ 
from a pedicel-portion. This small detail, described by 
Agardh and confirmed by Solms-Laubach 3 , is the first definite 
indication of a point of extreme importance. We have here 
the late formation of a secondary septum for the obvious 
physiological purpose of delimiting the reproductive coeno- 
cytic mass of protoplasm ; that is to say, the Dasycladaceae 
may form septa of two kinds : first, those which occur in 
connexion with the assimilatory processes ; secondly, those 
formed in correlation with the necessity for the isolation 
of the developing gametes. The septa of the first order 
indicate a high degree of specialization of the leaf as an 
assimilatory organ ; the septum, by preventing extensive 
streaming movements of the protoplasm, under the stimulation 
of external agencies, provides for an even distribution of 
protoplasm and chlorophyll-corpuscles in the assimilating 
segments ; at the same time allowing free conduction and 
transfer of substances in solution in the cell-sap by the open 
pore. When the protoplasm of the segment has reached the 
end of its assimilatory activity, the pore is closed and that 
segment falls off. In the same way, the delimitation of the 
gametangium by a septum isolates the contained protoplasm, 
but allows free entrance by the pore to reserve carbohydrates, 
&c. ; when the supply is complete, the pore is plugged by 
a cellulose stopper. But it must be noted, that while septa 
of the first kind, by being fortunately placed at the points 
of ramification of the leaves, afford valuable landmarks in 
determining the comparative morphology of segments, the 
1 Monograph, Plate IV, Fig. 5. 2 Ibid. p. 39. 
3 Monograph, p. 30. 
