THE PTERYLOGRAPHY OF THE RUFFED GROUSE 743 



sends a lateral branch toward the wing but in the rufied grouse, as with most other gallinace- 

 ous birds, the main portion seems to extend laterally. This lateral branch is divided into the 

 sternal and axillar regions. The middle portion, also highK developed and well separated 

 from the lateral branch, is the abdominal region. The remaining portions of the tract com- 

 prise the inter-ramal, sub-malar and cervical regions. 



The inter-ramal region bears feathers which are erect or nearlv so. At the edges they 

 bend outward, mixing with those of the malar region, thus covering the sub-malar space 

 on the lower jaw. The sub-malar region is not well marked off from the inter-ramal and 

 bears similar feathers except for a gradual increase in size. 



The cervical region which extends to the base of the neck encloses the inferior cervical 

 space on the middle line. The ruff consists of about five rows near the mid])()inl of the 

 neck in which the feathers are more numerous and much larger. They are unique in their 

 silky, truncate tips, often with iridescence. The male differs from the female in the greater 

 number of feathers making up the ruff and usualK in their greater length. 



The feathers of the sternal and axillar regions protect the larger portions of the ventral 

 surface, primarily because they are much longer than those of the abdominal region. The 

 latter, while well separated from the other two, is poorly defined on the sides where the 

 lateral space of the trunk is more or less obliterated by small feathers. Thus it is, in a sense, 

 continuous with the tract of the leg. In life, however, the small feathers probably have very 

 little effect. In the illustration they are represented by the smaller marks. A gradual in- 

 crease in size posteriorly is well marked. Likewise, and possibly associated with decreased 

 protection from the sternal and axillar regions, there is a great increase in the proportion 

 of downy parts in the feathers of the posterior portion. 



Humeral. This bears the scapular feathers which cover the adjacent spaces as well as the 

 bases of the feathers of the spinal tract. 



Alar. Including all the feathers of the wing with the exception of those in the humeral 

 region, this tract is most important from a taxonomic standpoint and is also interesting, due 

 to the fact that in many cases feathers can be recognized as individuals and are quite con- 

 stant among related birds. Roughly, it is made up of the large flight feathers, the coverts 

 and the alula feathers. The flight feathers or remiges consist of the primaries attached to the 

 "hand", the secondaries attached to the forearm and a single carpal remcx between the two. 

 The coverts are regular rows of smaller feathers in a shingle-like arrangement protecting the 

 bases of the remiges as well as of the other coverts. They become progressivelv smaller to- 

 ward the forward part of the wing. The alula might be compared with the human thumb 

 although it actually is the renmant of a second finger. 



The relative lengths of the remiges produce a short wide wing suitable for the well-known 

 short bursts of rapid flight characteristic of this bird. Among the ten primaries the seventh 

 and eighth are longest and the first is shortest, counting from the innermost. 



The secondaries are more or less variable in number. Usually there are sixteen or seven- 

 teen, although, because the innermost are relatively small, oidv about fifteen are actually 

 functional as flight feathers. These smaller remiges are not attached to the forearm but in 

 the elbow region and are thus often referred to as tertiaries. Even though the first or outer- 

 most secondary is reduced, a gap in the wing does not occur because it overlaps the adjacent 

 primary. The remaining secondaries are all nearly equal in size. 



The greater primary coverts, like the primaries, number ten. They lie between the latter, 



