572 MR. ST, GEORGE MIVART ON THE [June 27, 
In Indris they do not become easily discernible till the last two 
dorsal vertebrze, but they are marked in the lumbar vertebree. 
In Tarsius these processes attain their maximum, not in the dorsal 
or lumbar, but in the anterior part of the caudal region. 
In the Nycticebine the metapophyses are not conspicuously * de- 
veloped in the trunk vertebrae, most so perhaps in Perodicticus. 
As to the extent to which the metapophysis can be traced back- 
wards along the spinal column, as might be anticipated, it is in Ateles 
that it can be furthest followed; its amalgamation with the anterior 
zygapophysis sometimes not taking place, in that genus, till the ninth 
caudal vertebra. In the other Cebid@ this union takes place gene- 
rally at from the fifth to the seventh, though in Mycetes not till the 
eighth caudal vertebra. In Lemur it generally occurs at about the 
seventh caudal. In almost all the long-tailed Simiide the metapo- 
physes are distinct in the first three, four, or five vertebrze, the amal- 
gamation with the anterior zygapophysis taking place at the fourth, 
fifth, or sixth caudal vertebra. In Jnuus and the very short-tailed 
Cynocephali, as in Man and the Stmiine, metapophyses are not at 
all or scarcely to be traced backwards beyond the sacrum ; in Indris 
they are scarcely distinct in the second caudal vertebra. 
As to the extent to which the metapophysis can be traced forwards 
along the spinal column, there is considerable variation. As has been 
already recognized by others+, it can often be easily distinguished 
even in the first dorsal vertebra; but I am not aware that its exist- 
ence in the cervical vertebree of any Primate has yet been observed ; 
Fig. 6. 
\aez [" I \\ 74 i 
Z yn \ 
iY 0) 
G i re O-< ay i) 
i Mati’ Us ay 
- Shug im mh 
Axis and four following cervical vertebree of Areles, from the Museum of the 
Royal College of Surgeons (nos. 4694, 4695). Nat. size. m. Metapophysis. 
nevertheless it is often more or less traceable in the cervical region, 
but most distinctly so in the genera Ateles, Perodicticus, and Arcto- 
cebus, and sometimes in Simia. 
In Afeles this process is plainly distinguishable f as far as the third 
* They are really well developed, but extend so little upwards as to be com- 
paratively inconspicuous. 
+ Prof. Owen on the Megatherium, ‘ Phil. Trans.’ part 2 for 1851, p. 727. 
} Especially in the cervical vertebre (nos. 4694-4696) preserved in the Museum 
of the Royal College of Surgeons, and in nos. 808d & 808 ¢ in the British Mu- 
seum, where the first two dorsal vertebra show the metapophyses advancing 
inwards and preparing, as it were, to underlap the anterior zygapophyses of the 
cervical vertebre. 
