44 Memoirs of the Indian Museum. Vor Av 
is the apparent impossibility of the sexual cells getting into the testis-sac, where they 
are to undergo ripening ; for whatever may be said as to the possibility of their 
getting out, when ripe, in order to enter the funnel, they are at least not motile when, 
in their early stages, before they even form the well-known morula-like masses, they 
are detached from the testis.! 
ON THE USE OF THE TERM ‘‘IRIDESCENT FUNNELS.” 
On dissecting many of the ordinary Indian earthworms, what appear to be the 
funnels of the male deferent apparatus are often conspicuous by their glistening or 
iridescent appearance; and we find that words like metallic, glittering, iridescent, 
glancing, glänzend, have frequently been used in descriptions. 
What I wish briefly to draw attention to, is the fact that the funnels themselves 
are not iridescent, but that this appearance is due to the ripe spermatozoa in their 
neighbourhood. The spermatozoa when fully formed constitute wisps or bundles of 
innumerable extremely fine threads Iying parallel to each other, and the iridescence 
is a consequence of the parallel arrangement. The phenomenon is the same as that 
seen in the well-known ‘ diffraction grating’ ; in the same way the separated cuticle of 
a worm is iridescent, in consequence of the parallel striae of which it is composed. 
While ripe spermatozoa, which have assumed the parallel arrangement, are thus 
iridescent in mass, sperm morulae and the various developmental stages of the sper- 
matozoa ate not. Sincethespermatozoa take on the parallel arrangement before their 
discharge by the sperm-ducts, a quantity of matter in the testis segments (or in the 
testis-sacs, if these are present) will often be found to be iridescent; and if the ripe 
spermatozoa cluster round the funnel, this will be concealed by an iridescent investing 
layer. 
As confirmatory, it may be recalled that in the Megascolecidae the spermathecal 
diverticula (which act as the storehouse for spermatozoa received from another worm) 
are frequently of the same glancing appearance. In some cases the flocculent mass 
of sperm morulae, etc. in a testis segment passes gradually into the iridescent material, 
without there being any definite separation between the two (I observed this in Megas- 
colex polytheca var. zonatus). In Drawida ghatensis a fragment of what might have 
been described as a large iridescent funnel, when broken off and teased, was found to 
consist entirely of spermatozoa (the ‘Samentrichter’ in Michaelsen’s figure of this 
species,—fig. 2,—is I think obviously merely bundles of spermatozoa). Finally, I 
have cut sections of the ‘iridescent funnels’ of Pheretima hawayana, after detaching as 
much of the surrounding matter from them as possible, and found, as was to be expec- 
ted, that the actual funnels were largely overlaid by a layer of spermatozoa arranged 
' If I might venture a further word of criticism, I would briefly advert on the non-correspondence 
of text and figures in the account of this worm. The segments occupied by the clitellum (xi—xiii) are 
said to be devoid of setae; but setae are shown on xi in fig. I and on xiii in fig. 8. The clitellum 
itself in fig. 8 seems only to extend over xii-1/2 xiii. The outline of the brain is said to be very slightly 
concave behind ; but figs. 1 and 4 show it as slightly or markedly convex. It is hardly likely that the 
writer has prepared text and figures from different species; is the species variable in these points? It 
would have added to the value of the description if (supposing this to be the case) it had been so stated. 
