“Tree-Ducks’” of the genus .Dendrocygna. 65: 
Fig. 34. Superior view of the skull of a Canvas-back.  Mandible 
removed. Same specimen as shown in Fig. 27, Pl. 5. 
The skulls in Figs. 35—38 are all from adult specimens.; the Ba 
are all natural size. They belong to the Collections of the U. S. Nation. 
Mus. Numbers alone are given under the several Figures. 
Fig. 35. Left lateral view of the skull and mandible (detached) 
of a specimen of COhloephaga hybrida (No. 1820). 
Fig. 36. Superior view of the skull of a specimen of the Mallard 
(Anas platyrhynehos). Adult. Mandible removed (No. 17118). 
Fig. 37. Right lateral view of the skull and articular mandible 
of a specimen of Nettion carolinensis (No. 19469). 
Fig. 38. Left lateral view of the skull and detached mandible 
of a Mallard; the same specimen as shown in Fig. 36 of this Plate. 
Bilatierz 
Fig. 39. Superior view of the skull of a specimen of the 
Whistling Swan (Olor columbianus), mandible removed. Adult. Natural 
size (No. 19411, Coll. U. S. Nation. Mus.). i 
- Fig. 40. Same skull as shown in Fig. 39. Right lateral view with 
mandible detached (see Figs. 41—-43). 
Fig. 41. Basal view of the skull of Olor columbianus. Mandible 
removed. Same specimen as figured in Figs. 39 and 40. Nat. size. 
Fig. 42. Mandible from the skeleton which furnished the skull 
of the Swan shown in Figs. 39, 40, and 41 (O. columbianus, No. 19411). 
Seen from above. Nat. size. 
Fig. 43. Same mandible as figured in Fig. 42. Seen from below. 
Nat. size (0. columbianus, No. 19411). 
Bileatens 
Bones of a skeleton of a specimen of Dendrocygna autumnalis. Adult. 
Reduced. Extreme length of skull measures 95 mm. No. 1491, Coll. 
UT. S. Nation. Mus.). 
Fig. 44. Right lateral view of skull and detached mandible. 
Fig. 45. Left femur; anterior view. Length of this bone equals 
53,5 mm. 
Fig. 46. Right carpo-metacarpus; anconal aspect. Lower end 
of bone exhibits pathological enlargement. Length 55 mm. 
Fig. 47. Left humerus, anconal side Extreme length of this 
bone 97 mm. 
Fig. 48. Anterior aspect of the right tibio-tarsus and fibula. 
Extreme length of the tibio-tarsus equals 95,5 mm. 
Fig. 49. The sternum seen upon left lateral aspect. The first 
costal rib of the left side articulated in position. Length 86 mm (from 
carinal angle to mid-posterior point of the body of the bone). 
Zool. Jahrb. XXXVII. Abt. f. Syst. 5 
