THE NATURE OF HUMAN TICK-FEVER 
33 
rather long stout spines ; hypostome with two broad bilateral angular teeth 
on the anterior third ; mandibles extending considerably beyond the apex of 
the hypostome. Pain (PI. n, Fig. i) broad and stout, extending beyond 
the fully-extended mandibles ; each of the second and third segments with 
one minute, and one long stout spine, there are also two or three minute 
spines at the apex of the terminal segments. Margin of abdominal area 
finely and regularly crenulated ; cephalo-thoracic area also crenulated, but 
more faintly so and less regular. Dermis (PI. I, Fig. 7) with fine wavy lines. 
Spiracles apparently absent. 
Ovum (PI. 1, Fig. 1): In addition to the ^olden brown colour" described 
by the autnors, an irregular faint whitish polygonal reticulation and inter- 
rupted radiating streaks showed through the cuticle in the freshly laid 
examples. For particulars regarding the development of the ova see Report 
ante p. 15 and also the notes on the habits of the species in this appendix. 
When treated in a 10 per cent, solution of boiling potash (KOH) the eggs 
containing the mature larvae changed to a rather bright red colour, and 
instead of softening under the treatment became hard and opaque. It was 
found necessary, therefore^ to express the fluids from the body before 
maceration in the potash ; otherwise it was found impossible to examine the 
structural details. 
Fhe adult female of this species may readily be distinguished from O. 
savignyi, not only by the absence of eyes, as has already been pointed out 
by Pocoek (I.e.), but also by the presence of the interior bidentate apophyses 
and the apparently narrower base of the hvDOstome. Fhe authors of the 
Report of the Congo Expedition (p. 15) have called attention to the singular 
fact " that a clear fluid, in fairly large quantity, may oose intermittently 
from between the bases of the first and second pair of legs." They were, 
however, unable to find " any trace of an opening." I find, on examination, 
that there are groups of glands in the situations indicated, and also a third 
group between the base of the capitulum and the first pair of legs, and in 
addition to these there is a long bilateral series immediately behind the 
vaginal opening. All the glands have subcutaneous tubes, which later are 
finely branched and, as already stated in the diagnosis, these organs have 
much the appearance of bundles of muscular fibres. I find also that a 
group of similar organs exist in Ixodes hexagonus, Leach, but in this species 
the subcutaneous tubes are comparatively short and unbranched, and they 
bear a very striking resemblance to the so-called tubular spinnerets found 
in the Lecanid group of the Coccidae. 
It is important to note that the co-types (3) which were kindly identified 
by Pocock {I.e.) as O. moubata, are still in the collection of the School of 
Tropical Medicine. Some specimens of the latter were prepared for micro- 
scopical study, and were found on examination to be specifically identical 
with the specimens recently received from the Congo Expedition. There 
should be no doubt, therefore, as to the correct identity of the species. I 
have placed Neumann's var. cceens as a doubtful synonym, as, unfortunately, 
I have not been able to consult Neumann's original description, but Pocock 
(i.e.) considers it to be the same as Murray's 0. moubata. On the other 
hand, Ray Lancaster (I.e.) has quite recently ( 1905) identified some examples 
