374 PHYLUM ARTHROPODA. 
Congo, spread by Ornithedoros moubata ; a spirocheet disease in, Diiry, 
borne by Argas reflexus and A. persicus ; Texas fever or “‘red wy ‘em in 
cattle, carried by Boophzlus annulatus. The common sheep, ic in 
Bi 
io 
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Fic, 197.—Tick (Jxodes riduvius, Fic. 198.--Tick (/avdes " LUTUS, 
female), dorsal surface, showing the female), ventral surface -\_Aftey 
oval shield (.S/.).—After Wheler. Wheler. an 
H., Hypopharynx ; P., palp; Z./., L.ZV. R., Rostrum; P., palp; Go cent 
first and fourth leg. mee Pe , , aperture ; ST. stigma ; ae 
. 
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Britain is /xodes ricinus. It may be noted that mites have been fourg 
inside human tumours, and there are many facts suggesting that some 5¢ 
the small Acarines may share in spreading disease germs. Eve, 
_Demodex may play its part. \ 
Aberrant Orders or Classes ( 
i 
Order LINGUATULIDA or PENTASTOMIDA, ¢.g. Pentastomum 
teniotdes 
This strange animal is parasitic in the nasal and frontal cavities, etc., ‘ 
of the dog and wolf. It is worm-like in form, externally ringed, : 
without any oral appendages, but with two pairs of movable hooks near ' 
the mouth. The muscles are striated. The alimentary canal is very ; 
simple, without Malpighian tubes. A narrow circumcesophageal nerve- ! 
ring, without a brain, is connected with a single ventral ganglion. 
There are no sense organs nor trachese, nor is there any heart. The 
sexes are separate ; the males smaller than the female. 
Embryos within egg-cases pass from the nostrils of the dog. If they { { 
happen to be swallowed by a rabbit or a hare, or it may be some other 
mammal, the embryos hatch in the gut and penetrate to liver or \ 
