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THE AMERICAN NATURALIST [Vol. XLI 



of being almost straight [as it is in Puffinus]. The epieondylar 

 process projects much less forwards, and is continued down by 

 an elevated ridge to the surface of the condyle itself." (Forbes, 

 p. 422). 



Both radius and ulna in Puffinus are comparatively very slender 

 bones, the former, measuring 125 mm., is straight, and presents 

 a well-marked tendinal groove at its disto-superior aspect, over 

 the carpal enlargement. The ulna is likewise a very straight 

 bone in the shearwaters, with the elevations for the quill-butts of 

 the secondary remiges absent from the shaft. Its ends are but 

 very slightly enlarged, as they are in some birds. 



The skeleton of the hand has a length almost equaling the length 

 of the radius. The terminal finger-points are long, slender, and 

 pointed distally. Claws are absent. The proximal phalanx of 

 index digit is very long and narrow; its blade not being fenestrated 

 as in the Laridse. Large and small shafts of the carpo-metacarpus 

 are rather close together and markedly straight. Above its prox- 

 imal end is a spindle-shaped, free ossicle of some considerable 

 size. Possibly it occurs in the tendon of the tensor patagii longus 

 close to its insertional extremity, but it exhibits no articular facette 

 for the wrist, as does the os prominens of the Owls and others. 



The small phalanx of the medius digit is notably free, and 

 develops a tendinal tubercle upon its posterior border. Forbes 

 describes the pectoral limb as it exists in the ( )(raniti(ln\ in Ada- 

 compares the same as the skeh'ton of thi.-^ hmh is found io tlie 

 Diomedeina; {loc. cit. pp. 422, 423). 



Puffinus borealis has a femur that in length hardly e<|uals half 

 that of the tibio-tarsus ; it is somewhat antero-{)osteriorly arched, 

 the convexity being along the anterior border. Its upper eii<l is 

 also antero-posteriorly flattened, with the trochanteriaii crest 

 about absent, and the pit for the ligamentum teres much scoojhmI 

 out. A small free patella exists. In the tibio-tarsus the strikirg 

 feature is the enormous development of its procneniinl < rest \\ \ih 

 a corresponding sub-suppression of the ec to( lu iiiial one. This 

 is even still more marked in Puffinus crralopns. whcrr upon the 

 posterior aspect of the common prominence, a well-nuuked, 

 transverse groove exists, apparently for tlie accommodation of the 



