MONILIGASTER GRANDIS, A. G. B, 355 
0°24 mm. to 0°63 mm., but in variable species like M. sap- 
phirinaoides it varies in different individuals from 0'375 mm. 
to 0625 mm., so that I have judged of the normal size for the 
species after examining several individuals only. There is no 
appreciable variation in the size of different sete (full grown 
and unbroken) from any one individual. 
The presence or absence of all or one couple from Segment 
I1 is a good specific character, but I have found them present 
in individuals of a species where they are as a rule absent. 
The two setz of a couple are always very close together. 
The position of the rows of couples, i.e. the extent of the 
dorsal, lateral, and ventral gaps, is a very good specific cha- 
racter, and only fails, to my knowledge, in the case of what I 
consider to be hybrids between M. ophidioides, M. ro- 
busta, and M. sapphirinaoides, and between M. uniqua 
and M. pellucida. The position of the seta rows is only 
quite obvious (without mounting) in most species behind 
about Segment x111, but from that point onwards the relative 
distance of the rows to one another does not vary in the in- 
dividual. 
Occasionally in a species the distance between the two sete 
of a couple is greater than usual. My only instance of this is 
M. nilamburensis. 
Clitellum.—This, owing to its transient nature, would not 
in any case be a good character (it does not show externally for 
more than a month or two in the year, but I doubt very much 
whether, having been once developed, it would ever become 
unrecognisable in sections ; I have never found it so). So far 
as my observations go it always develops, and that upon Seg- 
ments x—x111, strictly confined to those segments, never com- 
plete ventrally (see M. grandis—clitellum), and never obscur- 
ing, or developing over, the intersegmental grooves. All the 
egg-capsules of Moniligasters I know (I have never found those 
of M. grandis!) are perfectly neatly formed and very globular. 
1 The small worm which so often occurs crawling in the mucus on M. 
grandis, is not, as I at first thought, the young of this animal; nor is it a 
Moniligaster at all. 
You. 36, PART 3,—NEW SER. BB 
