152 
THE STRUCTURE AND BIOLOGY OF HAEMAPHYSALIS 
PUNCTATA , CANESTRINI AND FANZAGO. I. 
By GEO. H. F. NUTTALL, F.R.S., W. F. COOPER, B.A., 
and L. E. ROBINSON, A.R.C.Sc. London. 
Plates XII—XVI. 
Introduction. 
The importance of various species of ticks in relation to the 
propagation of protozoal diseases, is so generally recognised that it 
has appeared to us eminently desirable to make a detailed study of one 
of the common species. Such a study has seemed to us specially 
necessary for the reason that our knowledge of these parasites is very 
imperfect, in spite of the fact that they possess an economic interest of 
the first order. Some of the diseases which ticks transmit, notably 
those due to the haematozoal parasites belonging to the genus Piroplasma, 
are among the most devastating affections of domesticated animals in 
many parts of the world, the useful animals which suffer from piroplas- 
mosis being cattle, sheep, goats, horses, and dogs. The disease known as 
“ Heart-water,” occurring in South Africa and affecting sheep, goats and 
cattle, is likewise tick-transmitted. A disease of the domesticated fowl, 
analogous to relapsing fever in man, likewise of economic importance 
and occurring in different parts of the world, has also been demon¬ 
strated to be transmitted from animal to animal through the agency 
of ticks. The fowl disease is due to a Spirochaeta which is conveyed by 
ticks; the same holds for human “ tick fever ” and a spirochaete infec¬ 
tion in cattle occurring in parts of Africa. Recent investigation appears 
to have clearly established the fact that a tick conveys spotted or Rocky 
Mountain Fever to man. Moreover it has been claimed that a Nematode 
worm, the Filarici per starts, parasitic in man, undergoes its development 
in a tick which is capable of conveying the parasite from one human 
