STERCORARIID^: JAEGERS, OR SKUAS. 



977 



S. pomatorhi'nus. (Gr. irchfia, TrwfjLaros, poma, pomatos, a Hap, lid ; fjls, pivos, hris, hrinos, 

 nose; in allusion to the cere. Fig. 682.) Pomatorhine Jager. Bill shorter than head, 

 or f the tarsus, about 2i times its height at base ; width about the same as height. Tail 

 (without middle feathers) less than half the wing; 1st primary little longer than 2d. Occiput 

 subcrested. Feathers of neck rigid and acuminate, their iibrilUe disconnected. Tail-feathers, 

 including middle pair, broad to tips, which are truncated, the rhachis projecting as a small 

 mucro; middle pair projecting 3.00-4.00, and not flat near tip, where they are twisted on the 

 shafts at an angle of 45° or more, so that the 

 vanes together form a nearly vertical disc visi- 

 ble in flight; the webs near the tip also length- 

 ened to about 2.75, those of other rectrices being 

 only about 1.75; exclusive of these projecting 

 feathers, the tail is slightly graduated. Tibiae 

 bare for 0.75, scutellate 0.50. Tarsi very rough, 

 anteriorly covered with a single row of scutella, 

 e.Kcept toward the tibiotarsal articulation, where 

 tliese scutella gradually degenerate into small, 

 irregular polygonal plates, with which all the 

 rest of the tarsus is reticulated. These plates 

 largest on outer side of tarsus ; on heel-joint, 

 and posterior aspect of tarsus generally, they 

 rise into small cones acutely pointed. Tarsal 

 scutella continuous in front with those on toes ; 

 polygonal reticulation on both surfaces of webs, 

 and under side of toes. Hallux extremely short, 

 its nail stout, conical at base, acute, little curved. 

 Anterior claws very strong and sharp; inner 

 most so ; middle expanded, but not serrated. 

 Webs broad and full, their free margins a little 

 convex. Cere straight, smooth, with trans- 

 versely convex culmen ; its lower border curves 

 gently upward to give passage to the nostrils. 

 Adult ^ 9, in breeding plumage: Bill horn- Fig. (^^2. - Pom-itorhine jager. 



color, deepening into black : feet black. Pileuin and occipital crest brownish-black, this color 

 extending much below eyes, aud occupying feathers on sides of lower mandible. Acuminate 

 feathers of neck light yellow. Back, wings, tail, upper wing-coverts, under tail-coverts as far 

 as flanks, deep blackish-brown. Under parts, from chin to abdomen, and neck all round 

 (except the acuminate feathers), pure white. Length 20.00 or more; extent 48.00; wing 

 14.0(»; tail 5.00 or more, with middle feathers projecting 3.00-4.00 farther; bill 1.75; tar- 

 sus 2.00-2.10; middle toe an<l claw rather less. Nearly adult : Generally the same, but with 

 a row of brown spots across breast ; sides under wings barred with white and brown ; dark 

 color of abdomen interrupted by touches of white. Feet wholly black ; middle tail-feathers 

 jirojecting about 3.00. Intermediate stage: The band of dark .'<pots across breast so enlarged 

 tliat the wh(de breast appears brown, mottled with white; sides umler wings consjiicuoiisly 

 liarred with white aud brown ; white of under parts continued over abdomen tn under tail- 

 niverts, tlie pure brown of these parts whicii obtains in the adult only appearing as transverse 

 bars. Upper tail-coverts and some of tlie wing-coverts barred with white. Bases of priina- 

 rits inferiorly white. Central tail-feathers only projecting l.(M) and not twisted. Feet irregu- 

 larly blotched with chrome-yellow. Yonng-of-the-year: Bill mucli smaller and weaker than 

 in tlie ailult, light-colored to beyond nostrils, where it becomes brownish-black. Feet mostly 



