DEVELOPMENT OP THE SKULL IN THE MAMMALIA. 
241 
somewhat everted (fig. 2) ; the exoccipitals are pierced by the hypoglossal nerve 
(%• 1, XII.) ; as usual, these foramina are very wide apart. 
The ossiculci auditus,—hyoid arch, and meatus-cartilage of Microgale longicaudata. 
The malleus (fig. 7, ml.) is remarkable in this, and in other small Insectivora; here 
the transverse extension of its main part is carried to the extreme, and here also the 
posterior angular process ( ag.p. ) is wrought into a very ornamental form, like a carved 
fruit-ornament; it is, as it were, suspended from the part which gives off the strong 
manubrium (mb.). The processes gracilis (jp.gr.) is about equal to the manubrium ; 
they are very far apart, and diverge, evidently; each is a twfisted and thick-edged 
blade of bone, the bach of which is in the inner side. The head is less definitely 
hooded than in the larger Centetidse, but the large posterior margin is more elbowed; 
the condyloid face is deep and oblique, but not large. The incus and stapes (figs. 8, 9, 
i, st.) are quite typical, relatively large, and very elegant in form; the short crus of 
the incus ( s.c.i .) is larger than in the Shrew; the stapes, most neatly finished, shows 
no interhyal on its neck. 
The hyoid arch has a separate epihyal above (figs. 1, 3, e.hy.), and has also an upper 
and lower ceratohyal (fig. 6, c.hy ., c.hy'.), the former is attached by ligament to the 
epihyal, above. The short hypohyals ( h.hy .) are articulated to a process of the basal 
bar (b.li. br.), whose thyrohyals (t.hy.) are not distinct, but short, and diverge greatly. 
Thus this small kind approaches our native Insectivora in the structure of its hyoid 
arch, which is much more perfect than in the kinds just described. 
When the meatus externus is dissected, and the lining cartilage opened out (fig. 10), 
it is seen that there are three imperfect annuli, separated by deep notches, inside the 
continuous concha, the proximal edge of which has also two round notches. 
The skull of the embryo of Ivhynchocyon cernei; 4 inches long from snout 
to root of tail. 
This is the largest of the Elejfhant Shrews of the African mainland, and is from the 
eastern part, near Zanzibar. 
The Macroscelidte, of which this is an outlying member and the largest of the 
family, are extremely unlike the insular forms from Madagascar, just described ; this 
particular kind is the more interesting as being a native of that part of the African 
continent which lies nearest to that large and most remarkable island, which is not 
African. The Macroscelidae, however, have a wide African distribution, continental 
and insular, and this large kind— Rhyncliocyon —is somewhat aberrant. 
So much does this type differ from the forms already described, namely, our native 
types and those from Madagascar, and also from those yet to be noticed, that, con¬ 
sidered from the standpoint of their cranial morphology, I am surprised at the colloca- 
2 I 
MDCCCLXXXV. 
