Gr. H. F. Nuttall. W. F. Cooper and L. E. Robinson 175 
in the dorso-ventral direction. Each palp is quadriarticulate, but the 
articles differ greatly in size and form. The proximal or first article is 
very small and is almost entirely hidden within the basis capituli ; it is 
narrow from side to side, elongated in the dorso-ventral direction, and 
obliquely inclined to a plane at right angles to the long axis of the 
capitulum in such a manner as to bring its ventral portion posterior to 
the dorsal portion: externally it is only visible ventrally, being completely 
hidden on the dorsal side by a scroll-like fold of chitin derived from the 
basis capituli. The second and third articles constitute the greater 
portion of the palp. The second article is irregular in shape, very 
convex on its ventral, external and dorsal surfaces and is provided with 
an oblique ridge (r.) which runs forwards and outwards from the proximo- 
internal angles and which defines another surface directed backwards. 
The third article, smaller than the second, tapers distally to a blunt 
rounded extremity which forms the extremity of the palp ; on its ventral 
surface, a little toward the internal margin, it bears a large pear-shaped 
fossa bounded by a raised margin, the latter being produced postero-in- 
ternally into a large blunt salient process ; in this fossa the comparatively 
minute fourth article is implanted. This article is very short and stumpy 
and is furnished with a crown of eight to ten short stiff hairs on its 
distal extremity. The interno-lateral aspect of the second and third 
articles of the palps is deeply concave, so that when adducted, the two 
palps ensheath the chelicerae and hypostome. The infra-internal margin 
of the palp is furnished with a single row of peculiar flattened feather¬ 
like hairs (PI. XV, Fig. 1); of these hairs, thirteen to fifteen are 
carried on the second article and about three on the third article: they 
are directed towards the mid-ventral line of the capitulum, the tips of 
those of each side almost meeting when the palps are adducted. The 
surface of the palps is furnished with a few simple hairs and pores. 
The buccal cavity. The buccal cavity is contained within the 
anterior part of the basis capituli; it lies between the bases of the palps, 
behind the hypostome, and is visible through the walls of the basis 
capituli in cleared specimens as a chitinous mass with a symmetrical 
outline of somewhat complex shape (the contour is indicated in PI. 
XIV, Figs. 1, 2) 1 . The walls of the basis capituli, bounding the anterior 
1 On account of the prevailing system of making drawings from specimens cleared and 
mounted in Canada Balsam or other highly refractive medium, without reference to the 
untreated specimen, the outline of the buccal cavity and other internal structures have 
frequently been figured by different authors in illustrations to specific descriptions of the 
Ixodidae. As such figures are usually supposed to represent external structures, the inclu- 
