RICHARDSON'S SKUA. 493 



hlacMsh-hroivn, the quills darher, the 2yrhnaries with the shafts 

 white ; anterior ^mrt of the forehead, the cheeks, throat, and 

 loicer part of the body ichite, the fore neck tinged icith brown, 

 the loicer wing-coverts and tail-coverts dark greyish-hroivn. 

 Female similar to the male. 



Male in Summer. — Of an elegant form, with the hody 

 moderately stout, the neck of ordinary length, the head rather 

 small, ovato-ohlong, and narrowed before, this species is much 

 inferior in size to the last, and somewhat less than the next, 

 from which it is at once distinguishable by the comparative 

 shortness of the two middle pointed tail-feathers. 



The bill is shorter than the head, rather slender, nearly 

 as broad as high, straight, with the tip decurved ; the upper 

 mandible with the dorsal line straight to the end of the cere, 

 then, on the unguis, rising a little, and arcuato-dccm-vate, 

 the ridge broad and somewhat convex, with a narrow groove 

 on each side, the nasal space covered by a thin plate, the 

 sinus short and feathered, the branches very narrow and con- 

 vex, the edges sharp and inflected, the tip compressed, 

 laterally convex, curved over the lower, thin-edged, but 

 obtuse ; the lower mandible Avith the intercrural space very 

 long and narrow, the branches sloping outwards and a little 

 convex, theif lower outline slightly concave, so that a very 

 slight prominence is formed at their junction, the dorsal line 

 very short, ascending, and very slightly concave, the edges 

 sharp and somewhat inflected, the tip narrow, sharp-edged, 

 rather obtuse ; the gape-line straight until near the end, 

 when it becomes decurved. 



The nostrils linear-oblong, wider anteriorly, placed nearer 

 the tip than the base, pervious, submarginal. Feet rather 

 short and slender, tibia bare for seven-twelfths of an inch ; 

 tarsus moderately compressed, with eighteen decurved scu- 

 tella ; the lateral and posterior scales small, oblong, convex, 

 so as to be a little rough to the touch. The hind toe is 

 extremely small and elevated, covered with small scales ; its 

 claw small, compressed, arched, acute; anterior toes of mode- 

 rate length, slender, the inner much shorter than the outer, 

 and having eighteen scutella, the third twenty-eight, the 



