152 Cincinnati Society of Natural Fiistory. 

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Fie. 11.—One-third natural size. Two lumbar vertebre: a, The third, anterior 
view, showing pits in base of neural arch; b, the fourth, posterior view, the epiphy- 
sis wanting. 
The transverse processes of the third and fourth lumbar are 
much broader, and are more bent forward and downward. ‘The 
longest neural spine is the fourth lumbar, and it slants more to 
the front, is 1.36 inches long, has a sharp blade in front, is. 
one-fourth of an inch thick at its posterior middle, and at upper 
extremity is .62 of an inch across, and one inch antero-posteriorly. 
The neural arch is decidedly flatter, on an average, than in 
Castor, is more nearly triangular, and approaches less to a semicir- 
cular outline in section. 

Fre. 12.—One-third natural size. Under surface and right margin of sacrum: 4a, 
anterior view; n, neural arch; 7, articular surface for innominate bone: p. posterior 
zygapophysis. 
The sacral vertebre are four in number, measuring unitedly along 
the median line 5.12 inches. The width anteriorly is 4.12 inches. 
The thin, blade-like transverse processes of the second, third and 
fourth are broken off about midway, outwardly. In Caster and 
Fiber the four exposed transverse processes blend into a continuous 
wing, which widens backward, and warps upward, more in Fier, 
less in Castor. ‘These blades have large perforations opposite the 
planes of union of the coalescing centra. These perforations 
increase in size from before backward. ‘The spinous processes 
also coalesce into a blade with a continuous thickened crest. ‘This, 
oe ee OS a a. ee 


