42 Memoirs of the Indian Museum. [Vor. VI, | 
normally formed functional setae, almost every specimen shows large numbers 
of setae of various sizes scattered about in the body-wall. These setae usually 
occur in parallel bunches, but may be scattered about quite irregularly. They 
lie in the inner layer of the body-wall parallel to the surface, and do not pierce 
the epidermis. In shape they resemble the functional setae.’’ The author con- 
siders that ‘‘in order to explain the observed phenomena it is therefore necessary 
to suppose that the seta-producing tissue has undergone a process of proliferation 
and spread from the region of the normal setae over the inner surface of the 
body-wall. This tissue appears to be in a state of unstable equilibrium in this 
species.’ It will be observed that the supernumerary setae are not said to be in the 
body cavity or surrounded by coelomic corpuscles, but in the inner layer of the 
body-wall. 
Finally, it is well known that in the Lumbricidae small brown grains, of about 
the size of a small pin’s head, may often be found in the coelom; these when broken 
up are seen to consist of brown granular matter derived from broken-down dis- 
coloured amoebocytes, in which are embedded discarded setae and nematode worms 
(Johnson, 6). I have found such grains, one of which on examination contained an 
entire seta, in a species of Perionyx, a Megascolecid. 
The above cases may not all be comparable together. In some at least, the 
abnormally situated setae or fragments are apparently in process of being got rid of, 
—in other words eaten away by the surrounding cells. 
The black particles in the corpuscular masses in Fridericia carmichaeli recall 
chloragogen pigment, and so too the brown granular matter in the grains found in 
the coelom of Lumbricidae, etc. It seems possible that the coelomic corpuscles, 
dissolving the substance of the setae, separate out the matter again in the form of 
the brown or black granules, and that this is perhaps ultimately got rid of by the 
nephridia ; or, of course, the effect of embedding the setae may merely be to render 
them harmless. 
As to whether the setae are in all cases, at first, normal setae, I should say not : 
it might be possible to suppose that the variously shaped fragments in Fridericia car- 
michaeli had been derived from normal setae by gradual solution under the influence 
of the corpuscles; but the long straight needles present a difficulty; and the smaller 
setae of Grania maricola appear to have been laid down originally of smaller sizethan : 
the ordinary functional setae. ' 
The chitinous cuticle of Arthropods and Annelids, besides being important or 
indispensable to its possessors in the rôle of an external protective covering, is never- 
theless suspected to be, in part, an excretion ; and if so the same must be said of the 
similar material which composes the setae. It would seem possible from the above, 
that this may be formed, on occasion, as rods or spicules purely in the way of excretion. 
These purely “excretory setae’’ are perhaps sometimes never got rid of, and remain 
to the end of life (as possibly in Grania maricola); in other cases, possibly, they may 
in turn be attacked, metamorphosed into substances that can be more easily disposed 
of, and finally eliminated through the usual channels. 
