_Megaladapis_, Forsyth Major, Phil. Trans., vol. 185 B, p. 15 (1894).
The cranium, about 10 inches long, indicates an aged animal three or four
times as long as the common Cat, which is an enormous size as compared with
any living Lemur. Brain-case straight, narrow, short, low, and situated at
a higher level than the facial region; an enormous lateral development of
the region between the eyes; orbits small in diameter, communicating freely
with the temporal fossa, protruding outwards and forwards, and surrounded
by a thickened ring; facial region elongate and bent upward; palate convex
downwards from front to back; ridges for attachment of the temporal muscles
uniting in a great central crest; frontal bones constricted behind the
orbits; maxillary bones behind the molar teeth greatly inflated by
air-cavities; the two halves of the lower jaw ossified together. In the
upper jaw the pre-molars have one outer and one inner cusp, and the molars
one internal and two external cusps, the former being deeply separated from
the hind outer cusp, and joined by a ridge to the front outer cusp. In the
lower {113}jaw, the posterior pre-molar has one outer cusp, a fore and hind
inner cusp (each joined by a crescent to the outer cusp), and a central
inner cusp; the three molars have two outer and three alternating inner
cusps, and to the outer side a basal cingulum; the posterior molar has a
strongly cusped heel.
MEGALADAPIS MADAGASCARIENSIS, Forsyth Major, the only species of the genus,
presents many marsupial and insectivorous characters and features which
show some approach towards the South-American Howlers (_Alouatta_), a
specialisation "not in the least," according to Dr. Major, "implying a near
relationship, but probably only an adaptation to a corresponding function"
implied in the "vocal organs of unusual size," which, he believes,
_Megaladapis_ to have possessed. Lemurine characters, however, predominate.
In the shape of its molars it is related to _Lepidolemur_, and still more
closely to _Microcebus_ and _Chirogale_, while by the characters of its
inter-orbital region it approaches to the Sifakas (_Propithecus_) and the
extinct _Adapis_.
The small diameter of its orbits suggests, according to Dr. Major, that in
habits this extinct giant Lemur was diurnal; and from the conformation of
its lower jaw "there exists," continues the same distinguished
investigator, "a strong assumption that, as in _Alouatta_, it was provided
with vocal organs of unusual size."
The age of this Howling Lemur, estimated either geologically or by years,
cannot be of very great antiquity. Its remains were found associated with
those of the giant Moa-like bird, the _Æpyornis_, of Tortoises and
Hippopotami, all now extinct, and of Crocodiles still living in the
interior lakes of the island. Some of these animals were certainly
{114}contemporaneous with the now vanished Dodo and the large flightless
Rail (_Aphanapteryx_), both of which were seen alive by Europeans little
more than two centuries ago, and it is not improbable that Megaladapis may
have been living in the Madagascar forests at the same period.
FAMILY LEMURIDÆ (_anteà_, p. 22).
In this family, and in its sub-family _Lemurinæ_ (because of its affinities
with _Hapalemur_), has to be included a large extinct species from Nossi
Vey, in North-west Madagascar. Its fossil remains were recently described
(P. Z. S., 1893, p. 532), but not named by Dr. Forsyth Major. They will
prove, he believes, when more fully known, to be the type of a new genus.
At present, however, owing to their incomplete state, it is not possible to
describe the species fully. "The Lemuroid nature of the specimen is at once
demonstrated by the great elevation and downward bending of the
post-orbital processes ... showing that the osseous ring of the orbit was
complete." Unusual for a Lemuroid is the very strong post-orbital
constriction of the frontals, a character, however, seen in _Adapis_, an
Eocene European form, and in _Hapalemur_. With the latter it agrees in the
voluminous cranial and very short facial portion, and the "cuttingly sharp"
inferior margin of its post-orbital process. Seen from the side, this
fossil cranium is almost vertically truncated behind, as in the skull of
_Alouatta_. The region between the eyes is vaulted by underlying
air-chambers.