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PLUMULARIANS. 
Br the Rev. THOMAS HINCKS, B.A., F.R.S. 
[PLATES CX., CXI.] 
HE Plumularians constitute a natural and strongly marked 
group of hy droid zoophytes. To the systematist they 
present salient structural characteristics ; to the biologist ob- 
scure and fascinating problems ; while they delight the eye of 
the least scientific observer by the gracefulness and delicacy of 
their feathery forms. Not only are the features of the family 
sharply cut and of very definite type, not only are its habit 
and expression singularly distinctive, but it also offers to us 
some morphological peculiarities, which, as it were, isolate it 
amongst its recent kindred. A sketch of this most exquisite and 
original group, as free as may be from the technicalities of the 
mere specialist, may possibly have some interest even for those* 
who are not themselves students of the Hydroida, and fittingly’ 
find a place in the pages of the Popular Science Review. 
The most obvious character of the family, suggested at once- 
by the name, is the plumous habit, which gives it its peculiar 
beauty. Each colony consists of a number of elegant plume- 
like shoots, delicately wrought in chitine, which either spring 
singly from the trailing fibre that binds them to weed or stone r 
or, borne on erect and branching stems, form large and composite 
growths which are almost like miniature palms in general 
aspect. Our British species are for the most part of .the simpler 
habit and of humble size ; but in the warmer seas the family is 
represented by lovely arborescent forms which sometimes attain 
gigantic proportions. Another salient character of the Plumula- 
rian family is found in the disposition of the calycles, or dwellings 
of the polypites, on one side of the ramules only, instead of on two 
sides, as in the allied family of the Sertularians. Each of the 
delicate pinnae of the plumule bears on its anterior aspect a 
single line of these little cup-like receptacles, exhibiting in the 
VOL. XIII.— NO. LII. Q 
