550 MR. ST. GEORGE MIVART ON THE [June 27, 
The odontoid process in some forms, e. g. Ateles, Lemur, and In- 
dris, is much shorter relatively to the length of the axis than in Man; 
it is generally continued forwards nearly or quite in the same plane 
with the centrum, but rises anteriorly, forming a marked angle with 
the centrum, in Lemur, Arctocebus, and Perodicticus, but not so in 
Nycticebus. 
The axis has, of course, two anterior zygapophysial articular sur- 
faces in those forms in which the atlas has two posterior articular 
surfaces, and but one in those in which the latter are confluent. The 
body is very much prolonged backwards in many forms, so that its 
posterior articular surface looks more or less upwards. This is well 
seen in A¢eles; but there is much individual variation in this respect. 
The third Cervical Vertebra.—The spinous process of this ver- 
tebra presents great variations in different forms. In most races of 
Men* it is strongly bifurcated ; but in none is it much elongated. In 
Simia and Troglodytes, however, it is very greatly elongated, and 
shows no trace of bifurcation. In all the other Anthropoidea it is 
the shortest of all the cervical spines, is sometimes directed forwards, 
and sometimes backwards, but is always quite simple, except in 
Mycetes (fig. 1), where it is more or less trifid, and therefore formed 
on the same type as is the spine of the axis in that genus. 
In the Lemuroidea we again meet with a distinctly bifurcated 
spinous process in Nycticebus ; and it is curious, that, while we find 
in this form a return in this respect to the human structure of the 
process, we find in other genera of the same subfamily (e. g. Pero- 
dicticus and Arctocebus) a lofty very elongated spine, similar to that 
existing in the Anthropoid genera Troglodytes and Simia. In Lemur 
and Indris the process is short and simple, as in most Anthropoidea ; 
but in Loris, Tarsius, and Cheiromys it is very rudimentary. In 
Galagot+ it is absent ; but two minute projections appear to repeat in 
this vertebra, and be serially homologous with, the lateral parts of 
the spine of the axis. 
The neural laminze have much the same proportion as in Man till 
we come to Ateles, where the antero-posterior as compared with the 
transverse diameter is first notably increased; but this elongation 
does not exist in the lower Cebide. 
In Lemur the relative antero-posterior diameter is greatly aug- 
mented, reaching to nearly half the total breadth; and in Indris 
this proportion is still further increased to two-thirds. In the Mye- 
ticebine it again decreases. In Indris the neural lamine are sepa- 
rated behind by an antero-posteriorly directed cleft or fissuret, the 
neural spine arising from the anterior end of the vertebra only, and 
not from its middle or posterior end as in Lemur and Ateles. 
The transverse process generally ends simply, without any bifurca- 
* In the skeleton of a male Boschisman, preserved in the Museum of the 
Royal College of Surgeons, the spinous process is simple (Osteological Catalogue, 
vol. ii. p. 832, no. 5357). The same is the case in the skeleton of a female in- 
dividual of the same race which is also in that museum. 
t See skeleton of Galago aillenti (no. 68 d) in British Museum. 
t Noticed by Prof. Owen, ‘ Osteological Catalogue,’ vol. ii. p. 717, no. 4631. 
