1888.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 231 



relatively occupy a mid-site on the mandibular side, the nasal being a 

 broader bone. I have figured a side view of the skull of this latter 

 Duck in Coues's "Key," second edition, where this feature may be seen. 

 Spatula and the Teals always have the extremity of the nasal median 

 processes of the premaxillary remain distinct to a large extent in the 

 craniofacial region throughout life (Fig. 1G). This is also well shown in 

 the Mallard, less so in Olor, and barely observable in Hutchin's Goose. 



Fig. 15. Right lateral view of the skull of Spatula clypeata, cf; life size. From a specimen in the 

 author's cabinet, and used throughout this article where this form is figured. I. lachrymal; l'mx. 

 premaxillary; </. quadrate; vt. pterygoid; pi, palatine; Mxp, maxillo-palatine. 



Mobility of the cranio-facial hinge, however, does not seem to depend 

 upon this condition, for in Glauciouetta, where a considerable amount 

 is enjoyed, this individualization of the nasal processes of the premax- 

 illa does not obtaiu to such a marked extent. 



Confining ourselves for the present to the lateral aspect of the skull 

 (Fig. 15), we find a notorious anatidiue character very pronounced in 

 Spatula, and this is the enormous development of the lachrymal (/) and 

 the consequent antero-extension of the lachrymo-frontal region. 



The descending process of this bone reaches backward toward the 

 long sphenotic apophysis, nearly to touch it in Glauciouetta, in which 

 Duck it usually lacks the terminal dilation so prominent in our subject, 

 and still more so in the Swans. The interorbital septum rarely shows 

 any deficiencies in its bony plate, the Golden-Eye being the only form 

 in which I have met such a condition, and in this fowl it is very small. 

 In all Anatidce the osseous pars plana seems to be aborted, simply a 

 low, bony ridge indicating where it is developed in other birds. The 

 mesethmoid is developed, however, as a strong median abutment ex- 

 tending far forward beneath thecrauio-frontal region. 



A vacuity usually occurs throughout the group, high up on the pos- 

 terior orbital wall, though the foramen for the exit of the olfactory 

 nerve is not notably large, and the one for the optic is distinct from the 

 outlying smaller nerve apertures about it. 



Most Ducks and the Brant have the track for the passage of the 

 olfactory to the rhinal chamber an open groove, while in Olor it may 

 be practically overarched by bone. 



As already intimated in a former paragraph, Spatula, in common 

 with others of the suborder, had a greatly lengthened sphenotic or 



