DEVELOPMENT OF THE SKELETON OF THE TUATARA. 27 
1s Q ie S T | Adult. 
10 ye Gs Uz U. U7 OE 
2s ? U. U. U7 (Of, U~ 
a 3. P: U. Uz. U. (Ub Uz 
Ss 4. PR U. (OE Uz U. (0% 
E 5. P. ut | UW. U. ? ? 
& 6. P U.t U. U. = FE. 
tlhe P: Cit (af U~, — F, 
8. PB: U.¥ U. U~. = F. | 
9, P. U. U. U. F. F. | 
10. | P. U. U. = P. ‘ain 
Wile 14 Uz. ? -- F, F. 
| 12. P. TF ? = ee a| B. | 
lay P: U. — — F, IH, 
14. 12. IP. — a F. 
115). iz, iB ae — os F. 
Wedel forte Oy Be P. = = = F. 
Fo Set nile lig BP. — — os F, 
a 18. > iB — | — F. 
19. P. iP. == = F. 
20, Pp: PB — — 1H 
be Iz. yan — — F, 
Bin) 12. IB — — i 
23. IP. P: = = F. 
| 24 IZ. TR — —- Li 
25 Pp if: | = ;  — — F, 
en ilitog. P. P. ? iS S F. 
aos VF Bs EZ ? — — F. 
28. pay) ee ? = _ Ee 
29. IP 12% ? — | = F. 
ef SO P. P. P. Peel ea F. 
= 31. P: ie Chev. Chev. | Chev. Chev.— F. 
| 2 32. PB. 1 Chev. Chev. Chev, Chev.—F. 
econ gee PB P) Chev. | Chev. | Chev. | Chev.—F. | 
| 34. P: IP. Chev. Chev. | Chev. Chev.—F. | 
| 35. P: P: Chev. Chev. | Chev. Chev. 
Yee ye hn ey y y ¥ 
| | | | 
Fig. 5.—Tabular statement of the order of arrangement and succession of intercentra for 
Stages P to T and the adult. 
P. Primary paired intercentra. U. Unpaired intercentra of primary order. — Intercentra absent. 
F. Secondary intercentra. Chev. Chevrons. + Medially constricted. 
Ribs and Sternum.—Ribs were attributed by Giinther to the segments between and 
including the fourth presternal (cervical) and the second sacral. Discriminating 
between the osseous rib as a “‘ pleuropophysis ” and its unossified ventral portion as a 
“hemapophysis,” he further distinguished between those vertebra in which the latter 
is fully developed as “dorsal” and those in which it is reduced as ‘cervical ” and 
‘“Jumbar ” respectively. 
For the caudal region he describes the presence of “transverse processes” and 
E 2 
