RELATION OF ARTHROPODS TO PATHOLOGY—MAROTEL. 715 
Thus, bovine piroplasmosis is inoculated by Rhipicephalus sanguin- 
eus, R. annulatus (fig. 10), and R. decoloratus; canine piroplasmosis 
by Ixodes ricinus, I. hexvagonus (fig. 9); Dermacentor reticulatus 
(fig. 12), and Hemaphysalis 
leachi. Ovine  piroplasmosis is 
transmitted by Lhipicephalus 
bursa; equine piroplasmosis by 2. 
evertsi (Theiler, 1904); tropical 
piroplasmosis by 2. appendicula- 
tus and fF. simus (Lounsbury, 
Theiler, 1904); and, finally, hu- 
man piroplasmosis may be con- 
veyed, at Madras, by an ixodid 
allied to Argas, the Ornithodorus 
savignyt (Christophers and Dono- 
van, 1905). 
B. Spirochetosis—The  spiro- 
chetes are spiral micro-organ- 
isms, the excessively slender body 
of which possesses a filiform nu- Fic. 9.—Iwodes hewagonus. Male. Ven- 
cleus and a lateral, undulating tral aspect. After Salmon and Stiles. 
membrane, without a flagellum (fig. 11). Classified to-day among 
the bacteria, consequently in the vegetable kingdom these microbes 
have been quite recently associated with the trypanosomes by Schau- 
dinn and others; that is 
to say, are regarded as 
animals. The greater part 
of them live a free life, 
being aquatic animals, but 
some are parasites of the 
blood, where they swim in 
the plasma. These are, 
therefore, exoglobular 
heematozoans. 
But it is known already 
that many diseases caused 
by them are propagated by 
Fig. 10.—Rhipicephalus annulatus. Male. Ventral , the ixodids. Thus, recur- 
surface. After Salmon and Stiles. rent fever in man, due to 
Spirocheta obermeieri, which in Europe is transmitted by bedbugs 
(Acanthia lectularia), is transmitted in West Africa by certain ticks 
which are still unidentified (Wellmann, 1905). Tick fever, another 
spirocheetosis of Central Africa, due to a spirochet very closely 
