L. E. Kobinson and J. Davidson 
43 
The floor of the buccal cavity is prolonged anteriorly in the form of 
a tongue-like process {tg.), which covers in the pharyngeal orifice. 
Apparently the function of this tongue-like process is to close the 
pharyngeal opening (o.ph.) while the salivary secretion is being forced 
directly into the wound made by the proboscis of the tick. The buccal 
cavity terminates in a cul-de-sac some little distance behind the 
pharyngeal orifice, into the postero-lateral angles of which the salivary 
ducts {d. sal.) open. 
The chitinous structures in this part of the capitulum are very 
complicated, as a study of the series of sections on Plate V will show. 
The basal portion of the hypostorne where it forms the floor of the 
buccal cavity and where it abuts on the foramina in the basis capituli, 
into which the basal articles of the palps are inserted, is much thickened, 
thus giving a high degree of rigidity to the basis capituli. The sub- 
cheliceral plate (sub.ch.p.) is a backward extension of the roof of the 
buccal cavity to which the dorsal dilator muscles of the pharynx are 
attached and which, as already mentioned, forms a guide upon which 
the expanded basal portions of the cheliceral shafts slide. Further 
reference will be made to these internal structures of the basis capituli 
in connection with the description of the alimentary canal. 
The Legs. 
In common with all the Ixodoidea, both nymphal and adult stages 
possess four pairs of well-developed ambulatory appendages; but, as has 
been remarked previously, the fourth or hindermost pair is suppressed in 
the larval stage. 
The legs are of moderate length, though relatively shorter than is 
the case in the majority of the Ixodidae. They are borne on the 
anterior half of the venti’al surface of the body, the two anterior pairs 
being directed forwards and the two posterior pairs backwards (see PL I, 
figs. 1 and 2, 1. i, ii, Hi and iv). Their colour is a pale yellowish-grey, 
and in the living animal they present a peculiar translucent glisteniirg 
appearance. Each leg is typically six-jointed. The descriptive termi¬ 
nology of Arthropod appendages, which is in general use, irray be 
conveniently applied in the present instarrce. Thus, the proximal or 
first article is termed the coxa', article 2, the trochanter", article 3, the 
femur ; article 4, the tibia ; article 5, the protarsus ; and article 6, the 
tarsus. Each leg is terminated by a rudimentary pulvillium, upon 
which is borne a pair of curved claws. The proximal fifth of each of 
