258 MEMOIRS OF THE CARNEGIE MUSEUM. 
The Axis. 
Five good specimens of the axis of Moropus were recovered, and fragments 
of others were found. Two of them, No. 1713, and the one belonging to the 
S40" spies an 
RNS; hi de 
Vy. SS Zi t | 
WEEE A Jf pik ! 
Zé Za fps 
ay 
iy 
wnt 
Fic. 24. Lateral view of axis of M. elatus (No. Fig. 25. Lateral view of axis of M. petersoni 
1604). xX i. (No. 1703A). X 4. 
mounted skeleton, No. 1604, are regarded by the writer as having possibly belonged 
to the cervical series of adults. No. 1703 is referred to M. petersoni and Nos. 
1724 and 1725 belonged in all probability to young individuals of M. elatus. 
The centrum is light, deeply excavated on both sides of the remarkably 
developed keel, which is a long, thin, vertical plate of bone expanding anteriorly 
Vie. 26. Diagrammatic lateral and ventral view of axis of M. elatus (No. 1604). A, peglike projection 
of odontoid; B, spoutlike projection of odontoid; C, anterior articulating surface of odontoid fusing with D, 
anterior articulating face of centrum; HH’, vertebrarterial canal; /’, fossa behind vertebrarterial canal; G, vertical 
keel of centrum; /7, posterior face of centrum; J, articulating face of postzygapophyses; J, anterior overhanging 
extremity of neural spine; K, posterior extremity of neural spine; LL, dotted line showing place of section 
represented in Fig. 27; M, outer extremity of transverse process; V, upper lamella of transverse process; O, 
lower lamella of transverse process: P, lower lamella of t. p. behind; Q, enlarged lateral rugosity at top of spine. 
