PROFESSOR OWEN ON THE AYE-AYE. 47 
produced anteriorly ; in the atlas it is as a small tubercle. The seventh cervical has 
a simple slender diapophysis, 2 lines in length; in the sixth it coalesces with the 
tubercle of a short pleurapophysis (7b. 6 ».), also confluent by the head with the centrum, 
and projecting outward, backward, and downward, with an obtuse end. The vertebral 
artery, in its forward course, enters the canal between the pleur- and di-apophyses. 
The pleurapophysis simply completes that bony canal in the fifth cervical, making a 
short angular projection outward and forward in the fifth, fourth, and third cervicals. 
The low, flat neural arch is narrowest in the fifth. The shape and disposition of the 
zygapophyses give an imbricate character to the union of those arches in the last six 
cervicals. The body of the axis is carinate below ; that of the atlas has the usual state of 
an ‘odontoid process’ (ib. fig. 4, ex); the hypapophysial bar (7b. fig. 1, ew) uniting 
with the neurapophysial pillars or crura of the atlas is carinate. Besides the wide 
canals for the vertebral arteries in the ‘ transverse processes’ of the atlas, the neural 
arch is perforated above the base of that process on each side for the passage of a 
nerve. 
The Skull.—The curve of the cranial vertebre brings, in the usual position of the 
occiput on the atlas, the premaxillary extremity (Pl. XIX. 2) parallel with the xiphoid 
cartilage (ib. ©), in the direction of the trunk’s axis. The skull of the Aye-aye, in 
comparison with ordinary quadrupeds of its size, is remarkable for the large proportion 
of the cranium to the face, and the extreme shortness of the latter in advance of the 
orbits. Its profile contour, from the upper border of the foramen magnum, is a con- 
vexity curving rapidly from the occipital to the parietal region, and continued with a 
bold convexity to the root of the nose, whence it slopes straight to the nostril. ‘The 
cranium is still more convex transversely (Pl. XX. figs. ] & 4); it expands a little in 
advance of the lambdoid ridge, and gradually, but very slightly, contracts to the 
postorbital processes ; these, meeting with the malar, complete the bony rim of the 
orbit, which opens widely beneath that part of the frame into the temporal fossa. 
The basioccipital extends to the fore part of the large tympanic bullz (ib. fig. 2, m), 
to abut against which its margins are slightly produced; it is smooth and slightly 
convex below, without hypapophyses. The occipital condyles are long and narrow, 
about 2 lines apart at their under ends, and extending upward and outward to the 
middle of the foramen magnum. The plane of this opening forms with the basi- 
occipital an angle of 125°, its aspect being downward and backward: the foramen is 
nearly circular, 64 lines in diameter, that of the cranial cavity being 1 inch 7 lines across 
its widest part transversely. The paroccipital is a low eminence, and the mastoid 
(ib. figs. 1 & 2,8) in front of it is hardly more prominent; neither process extends 
freely downward. The superoccipital is a thin plate moulded on the middle and lateral 
lobes of the cerebellum, and showing outwardly their respective prominences. The 
mastoid is impressed by the pit for the cerebellar appendage (7b. figs. 5 & 6, e). The 
lambdoid suture is nearly in the line of the low transversely arched ridge; it is a 
