156 MEMOIRS OF THE CARNEGIE MUSEUM 
Antero-posterior diameter of centrum of fourth caudal .............0..2.20.ce cee cee eee see eee eee eee 6.5 mm. 
Transverse diameter of centrum of fourth caudal.............. .....eccc ccc cee ese eee ere eee ce eeees eee 4.5 ‘ 
Vertical fs ss fe yiliealeaeaocnea cho ssecomdank cane baacdangvosencHoaEaCuudoaon 45 
Total height of fourth caudal, including tubercle.....................cccceecee eee eceeceeneeeeeeee Gr ee 
Antero-posterior diameter of centrum of eighth caudal 6.5 ** 
Transverse es st ts ss ae 
Vertical x ye 4 ~ ye De 
Antero-posterior  ‘‘ se eleventh ‘‘ yf 
Transverse uf “ a of Rie 
Vertical ue wee uy a Sai 
Tue Fore-Lims. Pl. XVIII. 
The left scapula in Steneofiber fossor is fairly complete in the type. In the cotype 
the scapula is complete, and this one is figured together with that of the type (see 
Pl. XVIII, fig. 2). This bone is conspicuous on account of the heavy and high spine. 
The lower border of the latter arises abruptly on the external face of the scapula 5 
mm. above the glenoid cavity, then descends again in acurved line to form the very 
broad acromion process. ‘This process extends much below the glenoid cavity. 
The spine forms a sinuous curve, and continues to the extreme superior border. It 
divides the narrow blade so as to form a slightly greater prescapular than postscap- 
ular fossa. The glenoid border forms almost a straight line from the glenoid cavity 
to the suprascapular border. There is no constricted neck above the glenoid cavity 
on the glenoid border. On a direct side view the spine is seen to greatly overhang 
the postscapular fossa. The latter is concave the entire length of the bone. The 
coracoid border of the scapula takes its origin at the base of the metacromion pro- 
cess, and continues in a curved line to within one fourth of the distance to the supra- 
scapular border, where the blade is broadest; then.it gently curves to the superior 
end. The superior half of the coracoid border is turned out so that it forms a con- 
cavity on the blade of the prescapular fossa. The suprascapular border is compara- 
tively heavy. There is a heavy metacromion process, which is curved inward and 
backward. The glenoid cavity has an oblong antero-posterior articulation for the 
humerus, and is somewhat similar to that of Aplodontia and Cynomys. There is a 
neck on the scapula above the glenoid cavity on the coracoid border similar to that 
in the beaver. The internal surface of the blade, especially superiorly, forms an 
open, reentrant, 3-shaped curve, like that seen in the beaver. The internal face 
of the scapula in Cynomys has sharp ridges running parallel with the long axis of 
the bone. ‘This is also seen, in a less degree, in Aplodontia. These ridges are not 
sharp, and are gently curved in Stencofiber fossor, and are here more nearly like those 
in Castor. In fact, the bone as a whole, with the exception of the well developed 
