230 
MR. W. K. PARKER ON THE STRUCTURE AND 
The stapes (st.) is thoroughly typical, having an unusually large foot-hole. I see 
no interhyal in the hinder of the stapedius muscle (st. to., see also Plate 32, fig. 7). 
The very Marsupial os hyoides (fig. 9) has small, unossified hypohyals ( h.liy.) on a 
transverse basihyal (b.h.br.) ; this is ossified now, and so are the thyrohyals (t.liy.) 
which are now segmented from it; they were not in the last stage (Plate 32, fig. 8). 
Going back again to the olfactory region, we find that the nasal, inferior, upper, 
and middle turbinals (fig. 10, n.tb ., i.tb., u.tb., m.tb.) are large and well developed, but 
at present they are cartilaginous. 
For a description and figures of the adult skull the reader is referred to Dr. Dobson’s 
invaluable work (Part I., p. 72 ; and Part II., plate 8). The whole structure is as much 
modified from what I have shown in the young (Third Stage) as that is from the skull 
of the unripe embryo (Second Stage). Its great length, and the large size of its 
transverse and longitudinal crests, make it one of the most remarkable skulls in the 
whole Order. 
On the skull o/’ITemicentes (sub-adult). 
For figures and a description of the adult skull of this type the reader is referred to 
Prof. Mivart’s Paper (Proc. Zool. Soc., Jan. 17, 1871, p. 5S), and for a further 
account of this type to Dr. Dobson’s Monograph (Part I., p. 69). 
Fortunately, my specimens—one of Id. madagascariensis (Plate 34, figs. 1-5), and 
another of II. nigrescens (Plate 34, figs. 6-9)—were not quite full-grown, and therefore 
yielded me better results for my special work than older skulls would have done. 
On the investing bones of the skull of Hemicentetes. 
This extremely elongated skull gains its great length, as in most other Mammals 
with a long head, not by elongation of the premaxillaries, as in longirostral Birds, but 
by the great length of the maxillaries and nasals. 
The upper view (Plate 34, fig. 2) shows that the nasals (n.) are more than half the 
length of the bony skull; they are much separated in front, and their suture only 
reaches to the middle ; in their hinder half they are completely ancliylosed. The 
fore part of each is a mere style of bone ; the united hind part is a convex lanceolate 
tract, overlapped at its edges by the thin internal edge of the divaricated frontals (/). 
The facial plate of the premaxillaries (px.) is about a fifth of that of the maxillaries 
(to./'.), but the upper margin is extended backwards between each nasal and maxillary, 
so as to keep those bones apart for the front half of their related edges. Each 
maxillary shows two regions laterally, the lower or alveolar is seen in the distance in 
this view, but the upper is in full view, it runs well up to the badly defined orbit; the 
whole of this upper facial tract is a long, gently convex lath of thin, but strong, bone; 
it reaches a little further backwards than the nasals, and, below and behind, shows 
between itself and the alveolar part, the infraorbital opening (V 3 .). 
