702 GEOLOGICAL SURVEY OF THE TERRITORIES. 
PAW ES. OVie 
Fic. 47.—Cranium of young Centrocercus, three or four days old, viewed from above. 
Fic. 48.—The same; Jateral view, with lower jaw added, showing articular element 
detached. 
Fic. 49.—The same, viewed from below. 
Fig. 50.—Centrocercus. Lateral view of skull of ‘‘bird of the year” four months old; 
the hyoid arch has been detached. 
Fig. 51.—The same aged bird as in Fig. 50, showing the disarticulated segments of 
the four cranial vertebre: OV, neural arch of the occipital vertebra (epencephalic 
arch), first of the skull; OV’, its hemal arch in outline (scapular arch); so, super- 
occipital; eo, exoccipital; po, the connate paroccipital; bo, basioccipital; PV, neural 
arch of the parietal vertebra (mesencephalic arch), second of the skull; P. V.’, its heemal 
arch (the hyoidean); P, the parietal; ms, the mastoid; as, the alisphenoid; bs, the 
basi-sphenoid; gh, the glossohyal; ch, the ceratohyal; bh, the basi-hyal; uh, the urohyal; 
hb and cb, the hypo-branchial and cerato-branchial elements of the thyro-hyals, 
respectively; F. V., neural arch of the frontal vertebra (proencephalic arch), third of 
the skull; F. V.’, its hemal arch (the mandibular); Fr, the frontal; x, the site of the 
postfrontal in some of the class; 0s, the orbito-sphenoid in outline; ps, the basi-pre- 
sphenoid; Tp, the tympanic; ar, the articular; S. an, the surangular; an, the angular; 
se, the splenial element; and de, the dentary element; N. V., the neural arch of the 
nasal vertebra (rhinencephalic arch), the fourth and last in the skull; N. V.’, its hemal 
arch (the maxillary); N, the nasal; Pf, the prefrontal (ethmoid); Vr, vomer in out- 
line, as it does not occur in this bird, (see description in text); Pl, palatine; mx, max- 
illary ; 7. mx, intermaxillary (or premaxillary); 1, the petrosal; 2, thesclerotals; 3, the 
lacrymal; Pty, the pterygoid, the diverging appendage of Pl, the palatine; sq and ma, 
the sqguamosal and malar, respectively, are diverging appendages ot Tp, the tympanic. 
