For numbers see Fig. 60.

B. The Skull.

Fig. 60. A. Ventral view of the cranium of a Duck (Anas boschas).

B. Cranium and mandible seen from the left side. × 1.

1. maxillae.22. anterior palatine foramen.
2. premaxillae.23. basitemporal.
3. anterior nares.24. foramen leading into tympanic
4. nasal process of premaxillaecavity.
(fig. 59).25. bristle inserted into posterior
5. nasal.opening of carotid canal.
6. frontal (fig. 59).26. bristle inserted into posterior
7. lachrymal.opening of Eustachian
8. postfrontal process.canal.
9. parietal (fig. 59).27. bristle emerging through
10. jugal.anterior opening of carotid
11. quadratojugal.canal. Close by is seen the
12. quadrate.bristle emerging through
13. condyle of mandible.the anterior opening of the
14. posterior articular process.Eustachian canal.
15. dentary at symphysis. }28. fenestral recess.
16. basi-hyal.} (fig.29. maxillo-palatine.
17. uro-hyal.} 59).30. lambdoidal crest.
18. basibranchial.}31. rostrum.
19. vomer.I. II. IV. V. IX. X. nerve
20. palatine.foramina.
21. pterygoid.

The skull of the duck, like that of birds in general, is characterised (1) by its lightness, (2) by the contrast between the bones of the cranium proper and those forming the rest of the skull, for the bones forming the cranium proper are closely fused together, the sutures between them being nearly all completely obliterated in the adult, while the bones forming the face are loosely connected with the cranium proper; (3) by the prolongation of the face into a long toothless beak; (4) by the size of the orbits, and their position entirely in front of the cranium, so that they are separated from one another only by a thin interorbital septum.

For purposes of description the skull may be divided into

(1) The cranial portion.