palate may have been in amphicœlian Crocodiles we may never know; but the large relative size, the forward position, and the horizontal plane of the bony openings oppose the application thereto of any such special and complex valvular structures as anatomy has revealed in existing Crocodiles.
If the submergence of the Crocodile with its "large mammalian" prey should continue so long as to render it needful for the reptile to "take a fresh breath," it can protrude its prominent snout from the surface and inhale a current of air which will traverse the long "meatus" and enter the glottis by the chamber common to nose and windpipe, which is shut out from the mouth by the modifications of a "velum palati" and "epiglottis" above explained. The same effect results from the "uninterrupted tube" in the procœlian Crocodiles as in that of the Cetacea. A teleologist must admit that "the contrivance is admirable;" it is equally effectual in both cases, and a Paley might expatiate upon the diversity of means by which the end is attained.
But we have no ground for inferring such means from the structure of the bony palate in the fossilized skulls of the amphicœlians; nor does our present knowledge of mammalian life in the Mesozoic periods encourage any belief that it was needed.
EXPLANATION OF PLATE IX.
Fig. 1. Upper view of skull of Theriosuchus pusillus.
Fig. 2. Under view of the same skull.
Fig. 3. Side view of the same skull.
Fig. 4. Left maxillary, inner side view, young individual, of Theriosuchus.
Fig. 5. Eight maxillary, outer side view, of full-grown individual.
Fig. 6. Crowns of large canine and three following teeth, magnified.
Fig. 7. Dentary bone and fragments of mandible, inner side view.
Fig. 8. Portions of humerus, ulna, and radius.
Fig. 9. Femur.
Fig. 10. Outer surface of medio-dorsal scutes.
Fig. 11. Inner surface of ditto.
Fig. 12. Two dorsal vertebræ, under view.
All the figures, save 6, are of the natural size.
complete a safeguard of the larynx in an animal breathing air, but destroying its living prey by submersion in water."
Geoffroy St.-Hilaire, 'Description des Reptiles de l'Egypte,' p. 236.
Hunter had left a preparation demonstrating the same structure, which is described in the 'Catalogue of the Physiological Series in the Museum of the Royal College of Surgeons,' 4to, 1832, vol. iii. p. 72, Prep. No. 1466.
See also Cuvier, 'Leçons d'Anat. Comparée,' 8vo, tome iv. (1805), p. 284. "Les ouvertures internes des narines sont très en arrière dans cet animal, contre l'ordinaire des autres reptiles," which other reptiles include the Crocodiles not procœlian or Neozoic.
