334 BULLETIN UNITED STATES GEOLOGICAL SURVEY. [Yol.YI. 



form one broad process placed transversely with a mesial keel in front 

 as tlie only indication of its original device. 



The carotid canal seems to commence and terminate in the same ver- 

 tebrse both in Tetraonince and Odontophormw. 



Of the eminently characteristic dorsal bone little has to be said in 

 addition to what has already been noted above. The number of vertebrae 

 included in the anchylosis is never more nor less than four, and the 

 first vertebral ribs have no hsemapophyses ; so they never connect with 

 the sternum, though they invariably bear uncinate processes, and in many 

 species contribute a good share toward the stability of the thoracic 

 parietes. The metapophysial processes vary principally in their ex- 

 tent : in Bonasa, Ciipidonia, and Pedicecetes. In several specimens they 

 nearly cover the tops of the diapophysial arms. In Lagopus a narrow 

 bar defines them, connecting the extremities of the transverse processes 

 with comparatively few offshoots. In Tetrao canadensis the bone is very 

 long and delicate. In T. ohscurus it has the same general appearance as 

 in Centrocercus. The hyijapophyses develop after the common type, but 

 often irregularly; they are found to be missing on the ultimate segment 

 or rather the pelvic end of the bone in the Quails. 



The free and last dorsal may or may not have a hypapophysis; we be- 

 lieve it never does in the Odontoplwrince. It is overlapped by the ilia in 

 Gupidonia and the Sharp-tailed Grouse. We find this to be a very marked 

 feature in the last, and well marked among some of these birds sent me 

 by Capt. James C. Merrill, Medical Department United States Army, 

 from Fort Custer, Mont., at a time they were particularly acceptable, and 

 when this erratic fowl became suddenly and unusually rare in many 

 localities, so that the gift was reckoned at the time as more than val- 

 uable desiderata. As far as the sacral vertebree are concerned, the same 

 general plan seems to be carried out : sixteen seems to be the allotted 

 number among the Grouse and, as a rule, among the Partridges. In 

 these birds the sacrum, i. e., the anchylosed sacral vertebrae, is much 

 narrower, as is the entire pelvis, and much lewer perforations are to be 

 seen among the dilated j)rocesses that go to meet the ossa innominata. 



In Cupidonia and Pedicecetes the sacrum is very broad, conforming to 

 a pelvis in these birds that will be described further on. We find in a 

 specimen of Tetrao canadensis, for which we are greatly indebted to Mr. 

 Manly Hardy, of Brewer, Me., where the sacro-iliac anchylosis is so per- 

 fect, and original land-marks so obscure, that one might easily imagine 

 the pelvis in this individual as being developed from a very much fewer 

 number of ossiflc centres. The caudal vertebrae number Jive in all the 

 Grouse except Cupidonia and Pedicecetes, these birds each having dis- 

 tinctly six apiece. We would especially call the reader's attention to this 

 fact, because when we come to discuss the pelves of these two birds, and 

 recapitulate general skeletal data, it will be found that, as far as osteo- 

 logical simularities are concerned, they come very near to each other. 

 The coccygeal vertebrae, otherwise, in common with the pygostyle, show 



