34 
Hah. On shells and stones from deep water, commoOi 
from Falmouth to Plymouth. 
This species varies from one to six inches in height, a n< | 
is delicate and drooping when large. The trunk is divided 
by septa, between each of which are placed one or two ring 3 
of an inter-articular substance, which is well figured by 
Johnston; each internode gives off one pinna at its upp el ' 
end, which rests on a protuberance of the stem, anil gi' rfl3 
it a waved appearance. The joints of the pinnae are aP 0 
separated by the inter-articular rings. The cells are disla 11 
small, cup-shaped, situated on a protuberance of the into'' 
node, and their apertures are plain and even. Between the 
cells are two minute hollow teeth, visible only under a hig 11 
magnifier. 
Dr. Johnston, in his references, has not considered th» 
Ellis’ figure, pi. xi., no. 16, a A, refers to this species; or 
least he has not referred to it, as he has to the figure at pi* 10 
38. But no. 16, at plate xi., is a very good likeness of tho£ e 
I have found growing on shells on this coast, and figure * ’ 
appears to be a magnified representation of the same; thong 11 
Dr. Johnston thinks both refer to Piuntularia pinnata: 111 
P. pinnata, the pinn® arise from each internode, and^ th, 
vesicles are strongly toothed, while in P. setacea, as in EH* 3 
figure, there is only one pinna arising from each internod 
Dr. Fleming has united them under one name. The** 
appear to be three varieties of this species which has probabu 
given rise to this confusion. 
The first variety, the longest with the shortest pinn®> 
figured by Johnston at pi. xviii., tigs. 4, 5, and general . 
grows on stones : . 
The second, on shells, feather-like in appearance, and 1* , 
the figure of Ellis’ at pi. xl., no. 16, a, on which 1 have fo u, ‘ 
abundance of vesicles like those figured surrounding 1 
stem, and not placed in the axillae of the pinna? : . 
The third, always parasitical, and most commonly on 
Plumularia frutescens, is figured by Johnston, pi. xviii., “o' ’ 
and Ellis’ Corallines, pi. 38, fig. 4. 
BRANCHED SEA BRISTLES. P. Pinnata. “ Sie ^ 
plumous ; the pinna? alternate ; cells rather distant, on® 
each inlernode, campanulate, leaning, the mouth enti^, 
vesicles obpyriforui, strongly toothed above, Dilleinus- 
P’ucoides setis minimis iudivisis constans, Itaii, Syc^' 
vol. 1, p. 39. Serf, pinnata, Turton’s Lin., vol. 4, p- ^ „ 
Stewart’s Elem., vol. 2, p. 446. Plum, pinnata, John 3 
in Mag. Nat. Hist., vol. 6, p. 498. Aglaophenia pinu a 
Lamouroux’s Cor. Flex., p. 172. Plum, pinnata, Johnsto 
Brit. Zooph., p. 145, pi. xvii., figs. 4 and 5. 
