378 
Rhipicephalus sanguineus 
which can be traced the growth of the various structural characters 
mentioned above. 
As a similar and equally regular variability is exhibited by the 
African material, collected in the field, these results again confirm 
Professor Nuttall’s view that variation is due, to a considerable degree, 
to varying degrees of nutrition. 
REFERENCES. 
Cunliffe, N. (vii. 1913). The variability of Rhipicephalus pulchellus, etc. Parasi¬ 
tology, vi. 204-216. 
Nuttall, G. H. E. (vii. 1913). Rhipicephalus appendiculatus: Variation in size 
and structure due to nutrition. Parasitology , vi. 195-203. 
