586 MR. ST. GEORGE MIVART ON THE [June 27, 
LaGoTHRIx*. 
In this genus there are fourteen dorsal, four lumbar, and three 
sacral vertebree. The hypapophysis of the atlas is very largely de- 
veloped, as are the hypapophyses and chevron bones of the caudal 
region. The axis-spine has a trifid tendency. The cervical spines 
are not curved over in a forward direction, nor are there any cervical 
metapophyses ; but hyperapophyses are largely developed in at least 
the last three dorsal and first four lumbar vertebree, and the lumbar 
anapophyses are very long and strong. There are five caudal verte- 
bree with spinous processes, and seven with a complete neural arch. 
CrBuvs. . 
Wagner says+ of this genus, that the terminal caudal vertebre are 
intermediate in form between those of Ate/es and Mycetes and the 
slender terminal ones of the lax-tailed Cebide and of Hapale. 
Mycerrs. 
Manubrium (figs. 4 & 5, m) remarkably divided in the middle 
linet. Axis with a trifid spine ; hyperapophyses in the neck and 
trunk (figs. 1 & 2,4); no cervical metapophyses ; anterior cervical 
spines rather elongated ; hypapophysis of atlas produced very strongly 
backwards beneath the axis; terminal caudal vertebree thick ; some- 
times only four bones between manubrium and xiphoid cartilage §. 
In all the rest of the Cebid@ and in Hapale the posterior caudal 
vertebree are long and slender ||. 
Piruecia9. 
In this genus the ribs attain the greatest relative breadth of the 
whole order; and the costal element of the sixth cervical vertebra is 
scarcely larger than that of the fifth. 
BracHyuRws. 
Here there are sometimes four sacral vertebrae **, the sacrum being 
strongly concave antero-posteriorly, long, narrow, and tapering. 
CALLITHRIX. 
Sometimes in this genus there are but eleven dorsal vertebrae ++, the 
* Thave only seen two skeletons of this genus—one in the British Museum 
(nos. 43d, 50, 11, 22, 61), the other in the Museum of the Royal College of 
Surgeons (no. A 4718 a). 
+ Zep. Aol. 
{ As has been before observed, it is completely cleft in the specimen preserved 
in the Museum of the Royal College of Surgeons, as well as in the one in the 
British Museum; and De Blainyille speaks of it as “‘ profondément bifurqué” 
(Ostéog. Primates, Cebus, p. 16). 
§ E.g. in no. 44a in the Osteological Collection of the British Museum. 
|| Wagner, /.c., and in Suppl. to Schreber’s Siug. Abtheilung, vy. p. 97. 
“| See the skeleton of P. monachus in the Museum of the Royal College of 
Surgeons. 
** See B. calvus (no. 8064) in the British Museum; it has seventeen caudal 
vertebrex. 
tt As in C. personatus (no. 51d) in the British Museum. 
