348 Mr. J. W. Fewkes on a Method of 
other structures of Nanomia are identical with those of Agal- 
mopsis pictum, a genus to which I formerly referred Nanomia, 
the exceptional character of the cystons seems to me to 
separate it from Sars’s genus. 
The “ oil-globule”’ forms a swelling at the proximal end 
of the “ cyston,” and was not observed to be ruptured. There 
seems, in point of fact, to be no opening through which it can 
be discharged. Its regular form, its constancy, its position, all 
stamp it as an organ of some kind. If we regard it as a float 
of a new individual it differs very greatly from the adult float 
of Nanomia. If we consider it a pigmented accumulation of 
excretory matter we disregard completely its character as far 
as the examination which has been made goes. It seems as 
if it should be regarded as connected in some way or another 
with the function of the cystons, but how I am unable at 
present to say. 
Reviewing the data which have been brought forward, we 
have the following facts bearing on the discharges of a coloured 
fluid from organs of the body or the modification in colour 
due to irritation in Siphonophores. 
1. Certain Agalmidex, Forskalide, and Apolemide dis- 
charge a coloured fluid from their cystons. This fluid is 
regarded as an excretion and is supposed by Heckel in one 
case to be the means of protection, as the sepia of the Cepha- 
lopoda. 
2. A typical genus of Agalmide (Agalma) has pigment- 
glands on the bracts which discharge their contents when the 
covering-scales are broken from the stem. This discharge 
probably takes place on simple irritation. 
3. Certain Hippopodide and a single known monogastric 
Calycophore change colour somewhat on irritation (see Chun’s 
description above). 
4, Nanomia has a prominent pigmented “ oil-globule” at 
the base of the cyston, which has never been seen to discharge 
its contents. 
What conclusions may be drawn from the above state- 
ments? Are we dealing here with phenomena of a similar 
character, or have we organs with two or three different func- 
tions? Are these discharges when they occur simply the 
throwing off of excretions, or do they also serve for protection 
of the Medusa from its foes ? 
It seems not improbable that the physiological function of 
certain of the tasters, which are known as cystons in Lorskalia, 
is that of excretion. ‘This power of throwing off excretions 
may also serve for protection. Yet it must be borne in mind 
that all the Calycophoridee, the Pneumatophoride, and Hippo- 
