_Filaria loa: male._—Body filiform, cylindrical, measuring
from 25 mm. to 30 mm. in length, by 0·30 mm. in breadth, of
uniform thickness, except where it tapers at the head and
tail. The cephalic end tapers somewhat abruptly to the simple
mouth, which is destitute of papillæ and armature. There is
no distinctly marked neck, but there is a sort of shoulder
about 0·15 mm. behind the mouth, where a number of strong
muscular longitudinal bands originate to pass down the body.
In one of the specimens the extreme head end is retracted and
abruptly truncated, measuring at the free end 0·1 mm. across;
in the other worm this part is more conical, and in it a short
pharynx can be seen, which opens out somewhat posteriorly.
At 0·1 mm. from the mouth the diameter of the worms is 0·15
mm.; further back, at 0·6 mm. from the month, it is 0·25 mm.
The tail end is sharply incurvated and, perhaps, excavated
ventrally; it is not spirally twisted. The tail is provided
with well-marked lateral alæ, which can be traced forwards to
a point 0·3 mm. from the tip of the tail. At the base of the
anterior papilla the tail is 0·08 mm. in diameter. There are
five well-marked papillæ on each side of the ventral surface
of the tail. The three anterior papillæ are præanal and very
large, the most anterior being the largest. The papillæ are
closely approximated, stout, and bulbous at the free end; they
measure 0·04 mm. in length by 0·022 mm. in breadth. The fourth
papilla appears to be adanal or post-anal, and is rather more
separated from the third than the three anterior papillæ are
from each other, and is distinctly nearer the middle line; it
is also considerably smaller, 0·03 mm. by 0·01 mm. The fifth
and most posterior papilla is very much smaller than the others
and differently shaped, being conical and sharp-pointed. It
measures 0·014 mm. in length by 0·005 mm. in breadth at this
base. There are two slender and unequal spicules projecting
from one of the specimens. The cuticle is not obviously
striated, but is dotted over with a number of widely scattered,
nearly hemispherical, smooth bosses, springing abruptly from
the surface. There appears to be no definite arrangement of
these bosses; at all events, if they are arranged after a
pattern this could not be discerned. The larger bosses are
found towards the middle of the parasite; at the head and tail
they are considerably smaller, and in these situations they are
more sparingly distributed. The larger measure at the base 0·12
mm., and rise about 0·004 mm. above the general surface. The
extreme ends of the parasite are not provided with bosses, the
first met with being about 1·5 mm. from the mouth and tail-tip
respectively.
“Owing to the opacity of the specimens the details of the
internal structure cannot be made out. In one worm, as
mentioned, a short pharynx can be seen, but its continuation
into the œsophagus cannot be traced. The prolapsed testicular
and alimentary tubes in one of the specimens are collapsed and
ribbon-like; they are about 0·09 mm. in breadth.
“The following diagram roughly indicates what I conceive to
be the arrangement of the details of the under surface of the
tail.”
[Illustration: FIG. 6.