392 
MR. ST. GEORGE MIVART ON THE VERTEBRATE SKELETON. 
Fig. 11. Side view of four vertebre of the Great Auk (Alca impennis). Hy, hypaxial elements of category 
A, i. e. hypapophyses.. From the specimen No. 1151 in the Museum of the Royal College of 
Surgeons. 
Fig. 12. Under view of four ophidian vertebræ, showing the coexistence of hypaxial elements (hypapo- 
physes) with bifurcated paraxial parts. Specimen, No. 634 A, in the same Museum, 
Fig. 13. Side view of four vertebre of a Python. Specimen, No, 630, in the same Museum, showing the 
bifurcating paraxial elements. 
Fig. 14. Vertebra and rib of the Axolotl, showing the bifurcation of the rib both at its proximal end, 
where it is attached to the superimposed tubercular and capitular processes, and also at its dis- 
tal end. : 
Fig. 15. Rib of a Salamander, similarly bifurcating at each end. 
Figs. 16, 17, 18 & 19. Four vertebre of Murena Helena, seen from behind. Specimen, No. 36, in the 
same Museum. P, paraxial element; H, hypaxial element; PH, parhypaxial process. 
Fig. 20. Lateral view of the aortic arches and descending nerves (external to them) of Lepidosiren para- 
doxa. Copied from Professor Hyrtl’s Memoir, tab. iv. fig. 2. ch, the spine or chorda dorsalis ; 
O, part of the esophagus ; V, aortic root, whence diverge the aortic arteries, ascending outside 
the branchial arches; b, b, b, b, the gill-apertures between the branchial arches; /, the exit 
of the nervus vagus—the nerves descending outside the arches, and to the outer wall of the 
œsophagus. 
