560 MR. ST. GEORGE MIVART ON THE [June 27, 
The lumbar transverse process has sometimes its distal end antero- 
posteriorly expanded* ; and sometimes a process is developed from 
its posterior margin similar in form and direction to the anapophysis, 
but external to it, as in Cheiromyst and often in Lemur. In the 
last-mentioned genus there is generally a second posterior transverse 
process to each lumbar vertebra ; it projects from the posterior part 
of the side of the centrum, and appears to be serially homologous 
with that part of the centrum of a dorsal vertebra which articulates 
with the anterior part of the head of the rib. A trace of this pro- 
cess exists in Indris. 
The metapophyses and anapophyses are always, except in Tarstus, 
most conspicuous in the lumbar region. They are exceptionally 
rudimentary in Man, Troglodytes, and Simia. But the condition of 
these proeesses will be more fully described later. 
SacruM. 
This region attains its greatest relative length in the Gorilla; but 
in the Chimpanzee, the Orang, and the Gibbons it is longer relatively 
than in Man, i. e. longer compared to the total length of the cer- 
vical, dorsal, and lumbar vertebrze. It is shortest in the lower Simzide 
and true Lemurs. Of all the Anthropoidea below Hylobates, Ateles 
has considerably the longest sacrum relatively. 
The human sacrum is remarkable for the coexistence of certain 
characters, such as the very marked sacro-vertebral angle formed by 
it, the transverse and antero-posterior (vertical) concavity of its an- 
terior surface, the concurrence of as many as five or six vertebrze 
in its formation (three of them generally contributing to form the 
auricular surface), its great breadth and the gradual way in which 
it narrows posteriorly (below) without any sudden contraction, the 
large size of the foramina, and the small development of the spinous 
and other processes. Each of these characters, taken separately, is 
shared by some other form or forms of the order. Thus, as to the 
number of sacral vertebrze (a character which varies more or less with 
age), all the Simzine have almost always five at the least ; but in 7’r0- 
glodytes and Simia there are always five, without counting the last 
lumbar vertebra, which commonly anchyloses with the sacrum ; while 
in Hylobates there are rarely more than fivet in all, the first of these 
being probably in all cases the vertebra which answers to the last 
lumbar of Man. In all the other Anthropoidea there are generally 
only two or three sacral vertebree—rarely four, as sometimes in Oy- 
nocephalus, Ateles, and Brachyurus. Inthe Lemuroidea two or three 
is still the normal number; but in Jndris there are four, and in Pe- 
rodicticus and Arctocebus five. Inthe Simiine three vertebre § arti- 
culate with the ilium, as mostly in Man; but then the upper one of 
* E. g. Inuus in British Museum, no, 32d. 
+ See Prof. Owen’s Memoir on Cheiromys, Trans. Zool. Soc. vol. y. pl. xxi. 
figs. 7, 8. 
{ De Blainyille mentions seven sacral vertebrae (Ostéog. Primates, Pithecus, 
p. 24). 
§ De Blainville, 7. ¢. p. 25. 
