514 GEOFFREY SMITH. 
groove may be complete. In the second thoracic limb of 
Koonunga (text-fig. 21), and indeed, in all the thoracic 
limbs of this form, the fusion of the basipodite and propodite 
is complete, so that the limb appears to be constantly formed 
of seven joints instead of eight. In all cases, nevertheless, 
there are constantly three segments above the “ knee-joint.” 
In the female sex of all the three genera, the coxopodite 
of the fifth, sixth and seventh limbs bears on its internal 
TexT-FIG. 22. 
Paranaspides lacustris. Fourth thoracic limb. 
face a small setose lobe (text-fig. 24). The function of 
this lobe, which is entirely confined to the female sex, is 
unknown, but since the lobes are only present in the hinder 
limbs in the neighbourhood of the oviducts and spermatheca, 
it may be suggested that they assist the process of fertilisa- 
tion in some way. The openings of the oviducts in the female 
are situated on the coxopodites of the sixth pair of limbs 
(text-fig. 27). 
The seventh thoracic limb differs from the foregoing in 
that in Anaspides and Paranaspides the exopodites are 
