35 
llab. On shells, and on the hack of the Corwich crab, 
Or nnion. Polperro. 
This delicate species is commonly found about from one to 
'' r ° and half inches high, “ bnt sometimes attains the height 
? four inches.” It is of a delicate straw colour throughout, 
j the pinnae are rather lighter than the stalk. The stalk 
( | S divided at regular intervals into joints, is smooth and 
Bs titute of cells. The pinnse are alternate and arise in 
'fees from each internode, though I have seen specimens in 
I lc h they arose in pairs. Each pinna arises from an en- 
.^gement of the stein, and like the stem, is divided into 
^ 'nts. The joints or internodes are about five or sis times 
s long as their diameter and irregularly waved. The cells 
I ? transparent, unilateral, small, distant, cup-shaped and 
/ ,Q g on enlargements of the internodes their apertures are 
,. tulous and even. Between the cells, one on each internode, 
■j,| l minute curved denticle, with its convexity turned upwards. 
le vesieles are sometimes very numerously produced, and 
e axillary; when young, ovoid; but when the gemmules 
e fit for expulsion, the upper part bursts into deep in- 
1, , stations, giving the appearance, as Ellis says, of being 
u ' v 'ded like a coronet.” 
a 1 ‘"s species very closely resemble P. setacea in general 
j t P e arance and shape of the cells ; but is distinguished from 
v having three pinnae on each internode of the stem 
of one; and by having only one denticle between the 
,s instead of two. 
^UMULAIIIA CATHERINA. “ Stem plnmous, the 
Pmnae opposite, bent inwards ; cells distant, campanulate, 
Vlt h an even margin ; vesicles scattered, pear-shaped, 
®ootb.” Johnston. 
Pi 
p. yj Um, daria Catberina, Johnston in Mag. Nat. Hist., vol.6, 
p' fig g , 01,62. British Zooph., p. 147, vignette no. 8, 
' /9 > P- 148, fig. 16. 
On Pinna ingens, in deep water five leagues off the 
at *man; common. 
Hs 1|S ' s ffi e most slender of all the species I have seen, 
'tnv P ' nn * are opposite, and “ instead of being arched bend 
Co r) , s > so as to render the general form of the coralline 
pj tl ave on a front view, an appearance produced by the 
fa c „* or iginaUng not from the sides, hut from the anterior 
by 
,tls tead 
“ells 
? Ce of 
the stem.” Johnston. 
-- ...... The cells are minute, eup- 
pi D P e< > situated on an enlargement of the internodcs of the 
I . , fltlfl l\o t in n n n f li r, n a I I o n »• r\ v, <1 „ t Anmif, nil n lit., I . _ 1 I 
cl es ’ v, sible only under a very high magnifier. The vesi- 
tlre pear-shaped, with a contracted mouth frequently 
snd between the cells are numerous minute hollow 
