14 PBOCEEDINGS OF THE NATTONAL. MUSEUM vol.67 



Chloephaga leucoptera has a very curious flat tongue. Ante- 

 riorly there is a single row of very weak lateral spines or hairs 

 Avhich a little further back develops into three heavy conical tearing 

 " teeth." Posteriorly it ends in a patch of small spines. This is, 

 so far as has been seen, the simplest form found in the family. 



The swans have the typical structure found in the family, which 

 is modified, however, by having heavy tearing " teeth " along the 

 edges of the median groove. This is true of Cygnus gihhus, C. 

 buccinator, and C. columbianus. 



Coscoroba coscoroha has a very heavy organ, but the edges of the 

 median groove are smooth without corrified processes. 



Cereopsis novaehollandiae has a most aberrant form of tongue. 

 Typically there is a very weak row of lateral spines, which may be 

 entirely worn away as in the specimen illustrated (fig. 35). Pos- 

 teriorly there are various fleshy processes which may be covered with 

 weak spines, absent in the one figured however. 



The number of lateral " teeth " vary throughout the family and 

 roughly follows subfamily groups. 



Thus the Fuligulinae tend to have from three to five, usually four 

 on each side. While members of the same species may not show a 

 constant number the variation will be found to be within these limits. 

 This is true of Oideinia, C haritonetta, Histrionicus, Arctonetta, 

 Marila, and Erisinatura jamaicensis (fig. 29). 



On the other hand the Anatinae present from 5 to as high as 

 12 lateral spines. This is true of Dendrocygna, Anas, Dafla, 

 Poecilonetta, Mareca, Nettion, and Querquedula cyanoptera (fig. 9). 

 Spatula, being a broad and long tongued form, has as many as 12 

 on each side. 



Aix, Plectropterus, Cairina, and Dendronessa average four to the 

 side, while typically this group is marked by an absence of cornifica- 

 tion of the edges of the median groove. 



Throughout this group there is a similarity of tongue form that 

 makes each one recognizable as belonging to the family Anatidae. 

 The modifications that exist are all based on a type pattern which 

 is characterized briefly as a fleshy organ with at least one, and 

 usually two, rows of lateral hairlike processes, a few or all of which 

 may be agglutinated to form solid cornified toothlike projections. 

 In these instances it is notable that dissimilarity of diet has not 

 destroyed evidences of relationship. Conversely, similarity of diet 

 as comj)ared with unrelated forms outside the family has not pro- 

 duced similar tongues. As instance witness on the one hand the 

 tongues of several fish eaters — mergansers, loons, and grebes — and 

 on the other the ruddy duck with its diet closely following that of 

 the American coot, and yet without paralleling it in tongue pattern. 



