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ТУ. Оп new Species of Caulerpa, with Observations on the Position of the Genus. 
Ву GroncE Murray, P.L.S. 
(Plates LII. & LILI.) 
. Read 5th March, 1891. 
THE exact position of the genus Caulerpa among the Siphonee has always been a 
matter of uncertainty. The vegetative characters by which it is sharply distinguished 
from the other Siphonee are of so singular a kind that little beyond the multinucleate 
siphoneous thallus is shared with other members of the group. Its reproduction—I do not 
speak of the vegetative propagation by the separation of shoots, which teaches us nothing 
of the least moment as to the relationship of the type—is a mystery that has batfled the 
curiosity of investigators. Its position within the group, therefore, has always depended 
more or less on the taste and fancy of writers. The conspicuous character of the 
genus, in which the outward forms of higher plants are closely reproduced, has 
always drawn the attention of botanists. The wonderful resemblances to mosses, 
to lycopods, to coniferous and cactaceous plants, and even to the typical foliage of 
other flowering plants would have been in other circumstances inevitably attributed 
to some of those mysterious forces called “ protective resemblance” and the like, so 
incalculable in their operations except in the mind of the subjective naturalist. 
There is fortunately no room here for such speculations, and we may be content with 
the view that Nature appears to have executed in the forms of this genus a Zour de force 
in exhibiting the possibilities of the siphoneous thallus—in showing that it is possible 
for a unicellular organism to display the varied beauties of outward form characteristic 
of highly-organized types; to attain by means of a lattice-work of cross-beams within 
the cell-body that mechanical support effected by transverse septa and separate, 
differentiated cellular structures for other Algæ and for the higher plants. 
In seeking for grounds on which to assign a definite systematic position to the genus 
one naturally looks first to a small section of it to which several writers have attributed 
separate generic rank under the name of Stephanoceelium. This form varies in a marked 
degree from the typical Caulerpe, and it is precisely here that affinity with other forms 
might successfully be sought for. Тһе species C. verticillata, J. Ag. (= Stephanocelium 
verticillatum, Kuetz.,— Herpocheta charoides, Harv.), at first sight with the naked 
eye, is certainly suggestive of the verticillate Dasycladee ; but the resemblance amounts 
to по more than a suggestion which is after all equally applicable to other verticillate 
Siphonee, such as are found among Valoniacee—for example, Chamedoris annulata. 
This resemblance to the Valoniacee has been one of which, for reasons difficult to 
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