588 MR. ST. GEORGE MIVART ON THE [June 27, 
the atlas has but one posterior articular surface, the two posterior 
zygapophyses uniting in the middle line. The transverse process of 
the fifth cervical vertebra is sometimes simple, and does not bifur- 
cate. The transverse processes of all the cervical vertebre project 
more sharply backwards than in the Anthropoidea. The ribs are 
never so few as eleven pairs, while they are occasionally as many as 
sixteen pairs. There are sometimes as many as nine lumbar ver- 
tebree. The increase in breadth and length of the posterior as com- 
pared with the anterior dorsal vertebre is very slight. Sometimes the 
third, fourth, fifth, and sixth cervical vertebre are quite destitute 
of neural spines. The cervical vertebrze are often very much extended 
antero-posteriorly. The sternum is never formed of so few as two 
or three bones in the adult; and the first three caudal vertebrze are 
short. Except in the Nycticebina, the atlas is furnished with wide 
and long transverse processes; there are, with the same exception, 
never more than thirteen pairs of ribs, but (except in Indris) always 
hypapophyses and more or less complete chevron bones, and, as 
in the Anthropoidea, the neurapophyses are not perforated by the 
spinal nerves. 
InprIs. 
This very remarkable form presents us with spinal characters at 
least as marked and distinct from those of the other Lemuroidea as 
are the spinal characters of Man from those of the rest of the An- 
thropoidea. Atlas with one posterior articular surface only ; spine 
of axis extending forwards at the summit, but not backwards ; spines 
of third, fourth, and fifth cervical vertebree rather.elongated ; neural 
lamina of third cervical vertebra split behind, so that its spinous pro- 
cess springs from quite its anterior end; anterior zygapophyses ad- 
vancing much in front of the roots of the neurapophyses ; transverse 
processes of neither the third, fourth, nor fifth cervical vertebra bi- 
furcated ; neural lamina of seventh cervical vertebra shorter than 
that of any of the other cervical vertebrae; cervical region exceeding 
one-fifth the length of the spine (exclusive of the tail), and nearly 
five times as long as broad; lumbar vertebre eight* or ninef in 
number; spinous processes of lumbar vertebre vertical; neural 
laminze of the dorsal vertebree shorter, and those of the lumbar ver- 
tebrze scarcely, if at all, longer than those of the cervical vertebree ; 
sacrum often composed of as many as four vertebrze, and tapering 
posteriorly ; spinous processes of sacrum long and flattened at their 
summits; transverse diameter of thorax considerably exceeding its 
depth ; dorsal region less relatively extended than in all the rest of 
the order; cartilages of ribs slightly dilate before joining the ster- 
num{; caudal vertebrae few and more or less decreasing in length 
posteriorly § ; no trace of hyperapophyses ; no caudal chevron bones, 
* As in skeleton in the British Museum. 
+ As in skeleton in the Museum of the Royal College of Surgeons. 
t Noticed by De Blainville, ‘ Ostéographie,’ Lemur, p. 21. 
§ In the skeleton in the British Museum there are fourteen caudal vertebre : 
the first two are about equal in length; they then decrease in all dimensions to 
the sixth inclusive. 
