558 MR. ST. GEORGE MIVART ON THE [June 27, 
genera there are 6 or 7 lumbar-vertebree*, except Cebus, which has 
sometimes as few as 5, and Nycticebus and Perodicticus, which have 
often as many as 8. 
The lumbar region attains its greatest length in proportion to the 
other regions of the spine, exclusive of the tail, in Nyctipithecus, 
Chrysothrix, Colobus, Semnopithecus, Cynocephalus, and Loris. It 
is least in the Gibbons, Man, Ateles, Simia, and Troglodytes. ‘The 
last two genera, with Perodicticus and Arctocebus, are remarkable 
for the very slight increase in size of the lumbar series of vertebrae 
from before backwards, 
These vertebree have their length and breadth about equal in the 
Nycticebine and Tarsius; in Man, Troglodytes, and Simia, breadth 
is In excess, while length is so in most of the other forms. The length 
of the individual lumbar vertebrze compared to the dorsal (selecting 
the ninth dorsal and longest lumbar for comparison in each species) 
is greatest in the lower Cebid@ (more than double in Nycéipithecus, 
Chrysothriz, and Brachyurus), rather less in the lower Simiide aud 
Lemurina, still less in the Simiine and Nycticebine, and least in Man. 
The number of dorsal and lumbar vertebra, taken together, is 
greatest in Loris and Nyeticebus (23 or 24); small in Man, Troglo- 
dytes, and Simia (17), and Ateles and Hylobates (mostly 18). In 
the other Simiade there are almost invariably 19 trunk vertebreet. 
The proportion borne by the lumbar to the dorsal region is greatest 
in Indris, then in Nyctipithecus, Chrysothrix, and some Simiade 
(e.g. Colobus). In most forms the two regions are about equal ; 
but the lumbar is the shorter in Man, the Gibbons, and Orang, 
Ateles, and Troglodytes, in the Gorilla being less than half the dorsal 
region in length. ‘The beautiful sigmoid curve formed by the dorsal 
and lumbar vertebrze of Man exists in no other species; but the 
nearest approximation to it is found not in the highest Apes, but in 
Cynocephalus f. 
The neural spines are all vertical, or project more or less backwards, 
in Man, the Simiine, Ateles, and in the Nycticebine ; in some of 
the lowest Simiide some of them are also more or less vertical. In 
Indris the spine of the first lumbar vertebra is inclined slightly for- 
wards. All the lumbar spines project forwards in the other forms, 
especially in the lower Cebide, in Hapale, and in Lemur, in all of 
which they are very long, and arch over the vertebra next in front in 
a very marked way. In Galago (fig. 8,) a process projects back- 
wards on each side of each lumbar vertebra, above the posterior zyga- 
pophysis, the two of each vertebra closely embracing the forwardly 
* De Blainville mentions a Baboon in the Paris collection with eight lumbar 
and twelve dorsal vertebrae (Ostéog. Primates, Pithecus, p. 40). 
+ Ina Macacus radiatus, in the British Museum (no. 1103 ¢), the vertebrae 
are 12 d.+61.=18; in a Cynocephalus babouin (no. 36c in the same collection) 
the number is 13d.+71.=20. De Blainville mentions 12d.+81.=20. See 
Ostéog, Primates, Pithecus, p. 40, above referred to. 
t E.g. Cynocephalus porcarius (no. 35d in the Osteological Collection of the 
British Museum), which is a xatura/ skeleton, having all the ligaments, inter- 
vertebral cartilages, &c. See also the Mandril, no. 4719 in the Osteological 
Collection of the Royal College of Surgeons. 
