OSTEOLOGY OF BIRDS 



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smaller in size. I would remark here, however, that the cnemial 

 processes of the tibiotarsus of Harelda are rather more elevated, 

 reminding us in this particular of some of the lesser auks. And 

 there is yet another point to be noticed, and that is the metacarpal 

 bone of the pollex phalanx in the carpometacarpals is longer and 

 more parallel to the shaft of the metacarpus of the index ringer 



Fig. 32 Pelvic limb of C 1 a 11 g u 1 a islandica; right side. Natural size. Drawn 

 by the author; same skeleton as figure 31 



than it is in Spatula, and to some extent this is likewise the case 

 in Polysticta stelleri, a species wherein the appendicular 

 skeleton likewise closely agrees with that of S. clypeata. 

 Among the eiders and scoters (Somateria, Oidemia) the limbs are 

 powerfully developed, and the long bones long and strong. They 

 present essentially the same characters otherwise as are to be found 

 in the skeleton of these parts among the smaller ducks. Some- 

 times we find a species wherein one of the grooves at the back of 

 the hypotarsus of the tarsometatarsus closes over so as to convert 

 it into a tube for the tendon rather than an open channel, but this 

 is not of much import. A case of it is seen often in Oidemia 



