o4 MR. W. K. PARKER ON THE STRUCTURE AND 
it is in front of the great archway for the branches of the facial and the auditory 
nerve (VII., VIII.). There is a lesser aperture under the anterior canal, where the 
concavity is shallow, as in the Dasypodide, and not deep, as in the Insectivora and 
many other Eutheria; hence the “ flocculus” must be but little developed in these 
Edentata. The endocranial “setting” of the capsule is about two-thirds the breadth 
of the imbedded sense-organ which bulges, inwardly, and is, although confluent with 
the capsule here and there, yet everywhere well marked off from it, 
The relation of the three osseous centres—the basi-, ex-, and supraoccipital 
(b.0., €.0., 8.0.) 18 well seen; the basal piece is one-third longer than the cartilage in 
front of it, twice the length of the basisphenoid (b.s.) in front of that. There are four 
holes in the short exoccipital ; the largest of these, behind, is evidently the posterior 
condyloid foramen, the rest would appear to let out the hypoglossal (XII.) in three 
strands ; externally (Plate 8, fig. 1), it only has one passage for its exit. The deep 
oblique passage for the larger post-auditory nerves (IX., X.) is shown in this figure. 
The tnner view of the double mandible (Plate 9, fig. 9) shows some extremely 
important morphological points. The primary mandible runs from a point near the 
fore end of the secondary ramus to a point considerably behind it; it is therefore the 
longer of the two; moreover, it is in two parts, a short proximal, and a long distal, 
segment. The true swinging point of the primary mandible—the “pedicle” or 
“orbital process,” such as we see in the Ovipara—is suppressed in the Mammal ; hence 
the ‘ucus (or quadrate) has merely the secondary or hinder point of attachment, above, 
the short crus (s.c./.) or ‘ otic process,” The line of segmentation or condyloid face is 
sinuous or saddle-shaped, and the specially Mammalian process—the long crus (l.c.7.), 
with its inturned neck and flat orbicular head for articulation with the topmost 
segment of the hyoid arch—is well developed. The solid condyloid region of the main 
or distal segment, the head of the malleus, overlies the scooped tract that gives off the 
blunt “ posterior,” (p.ag.), and long foreturned “internal angular process” (manubrium 
mallei, mail.) ; this latter part is slender, pinched in the middle and pointed at its end. 
The main shaft or Mxcket’s cartilage (mk.) is pinched on its inner face proximally and 
then runs its course, gently arching downwards, and thickening in the middle as a 
strong terete rod. Where it joins its fellow, there a small basal rod (b,mn.) is given 
off which lies in the symphysis of the superficial rami. The outside part (d.) has 
already been described as seen from its outer side (Plate 8, fig. 3) ; here, in front of 
the dentary canal, a flange of bone is given off from the alveolar wall, which overlies 
MeEcKEL’s cartilage ; this tract is the continuous counterpart of the distinct splenial 
and coronoid of the Ovipara. 
The stapes (Plate 9, fig, 9, st.) or topmost segment of the hyoid arch is shown as 
dissected away with the double mandible ; its oval proximal head is seen sideways 
as a thick rim to this short flat rod. The length of the rod (not a stapes but a 
“columella”) is equal to the breadth of this proximal plate; its hind margin is 
concave, and its front convex. here is a short distal neck, with a circular flat head, 
