“Tree-Ducks’” of the genus Dendrocygna. 63 
Plate 3 
Fig. 10. Right lateral aspect of the head of Dendrocygna bicolor, 
Q ad. Photograph by author of skin, No. 135590, Coll. U. S. Nation. 
Mus. Natural size. Collected April 30, 1894 by Dr. EnGAR A. MEARNS 
at Unlucky Lake, San Diego, California. 
Fig. 11. Right lateral view of the skull and mandible (detached) of 
Cereopsis novae hollandiae. Slightly reduced. Extreme length of skull 
92 mm (No. 19711, Coll. U. S. Nation. Mus.). 
Fig. 12. Right lateral view of the skull and mandible (detached) 
of a specimen of Dendrocygna autumnalis, Q (No. 454). Slightly reduced. 
Extreme length of skull 98 mm. F. B. ARMSTRONG collector (Texas). 
Fig. 13. Right lateral view of the skull and mandible (detached) of 
a specimen of Hymenolaemus malacorhynchus, Q ad (No. 19024, Coll. U. 
S. Nation. Mus.). Slightly reduced. Extreme length of skull 90 mm. 
Fig. 14. Right lateral view of the skull and mandible (detached) of 
a specimen of Ühloephaga poliocephala, Q ad. (No. 18202, Coll. U. S. 
Nation. Mus.). Slightly reduced. Extreme length of skull 81 mm. The 
extreme lengths of these four skulls were measured, in each case, from 
the most anterior median point of the superior mandible on a direct 
straight line to the most posterior median point on the summit (exter- 
nally) of the occipital protuberance. 
Plate 4. 
Fig. 15. Superior aspect of the skull of Dendrocygna aulumnalis. 
Mandible removed. Same skull as shown in Fig. 12, Plate 3. 
Fig. 16. Superior view of the skull of Hymenolaemus malacorhynchus. 
Mandible removed. Same skull as shown in Fig. 13, Plate 3. 
Fig. 17. Superior view of the skull of Cereopsis novae hollandiae. 
Mandible removed. Same skull as shown in Fig. 11, Plate 3. 
Fig. 18. Superior view of ihe skull of Chleophaga poliocephala. 
Mandible removed. Same skull as shown in Fig. 14, Plate 3. 
Fig. 19. Right lateral view of the skull and mandible of a 
specimen of Branta canadensis, adult. Somewhat enlarged (No. 17980, 
Coll. U. S. Nation. Mus.). Extreme length of skull 123,5 mm. 
Fig. 20. Os furcula of Branta canadensis. Right clavicle shows 
external view. Slightly enlarged (No. 17980, Coll. U. S. Nation. Mus.). 
Fig. 21. Anterior view of left femur of Branta canadensis, adult 
(No. 17980, Coll. U. S. Nation. Mus.). Slightly enlarged. Extreme 
length 87,5 mm. 
Fig. 22. Leftscapula; dorsal surface of Branta canadensis (No. 17980, 
Coll. U. S. Nation. Mus.). Slightly enlarged. Extreme length (chord of 
its arc) 111,5 mm. 
