NATURAL SCIENCES OP PHILADELPHIA. 
137 
the feathers’before and below the eye, and on the sides of the bill, being of 
this color. Neck all round, but especially the sides of the head and the 
peculiarly formed feathers on the latero-nuchal region, light straw yellow. 
Whole upper parts, with upper wing and tail coverts deep slate ; which, on 
the primaries, secondaries,* lateral tail feathers and distal half of central 
pair, deepens into a pure lustrous brownish black. Under surface of wings 
and tail deeper slate than the back, but not so deep as the upper surfaces. 
Chin, throat and upper breast white ; gradually becoming obscured with 
dusky plumbeous, which deepens posteriorly, so that the abdomen and under 
tail coverts are nearly as dark as the back. Rhachides of first two or three 
primaries pure white, deepening into brownish black at their extreme apices; 
of the other primaries, and of the tail feathers (including the central pair) 
brown, except just at the base, deepening into quite black terminally. The in- 
ferior surfaces of all the rhachides are white for nearly their whole length. 
Length of culmen 1-15 inches; gape 1-70; cere *60; unguis about the 
same; gonys *30; from feathers on sides of bill to tip *90; wing 12*50 ; tail 
6*25 ; central pair 14*00 to 16-00 ; the projection 8*00 to 10-00 inches ; tibiae 
bare *75 ; tarsus 1-60 ; middle toe without claw 1*40. 
Habitat. — Sea coasts of America and Europe, particularly in the higher 
latitudes. Interior of Arctic America. — (Kennicott.) 
The changes of plumage of this species are strictly homologous with those 
of S. parasiticus ; and it is therefore quite unnecessary to present them in this 
connexion. 
As before remarked under head of parasitica , it is exceedingly difficult, if 
not quite impossible, to determine positively to what species the “ parasitica ” 
and u cepphus ” of the older authors refer. This confusion is occasioned 
partly by the brief and vague diagnoses given, and partly by the fact that the 
two species were really confounded by authors (except Brisson) until com- 
paratively quite a late period. Even so late as 1820 Temminck does not 
separate the two : his description applies to either, and the synonyms of both 
are indiscriminately adduced. From which state of things it results that 
nearly all the older names and citations may be without difficulty referred to 
either species. This in effect has been really done ; some authors, for ex- 
ample, considering Briinnich’s or Linnaeus’ parasitica to be th.e long-tailed 
species, and others holding a contrary opinion, until the identification of 
these names has become almost a matter of choice, or rather of tacit agree- 
ment among ornithologists. This is the more to be regretted since on it de- 
pends the question whether the common or the long-tailed Jager is to be called 
parasiticus. A glance at the synonymy of the species will show that authors 
have been about equally divided on these points. Before the introduction of 
u Richards oni” by Swainson, the common Jager was usually called 11 para- 
sitica but after the adoption of this name “ Richardsoni ” by Temminck, for 
the common Jager, the name parasitica was for some years almost univer- 
sally applied to the long-tailed species. In the year or thereabouts, 
the name of Buffoni was proposed by Boie for the long-tailed species, and 
was adopted by many writers ; while others had recourse to Brisson’s old 
name “ longicaudatus .” Within the last few years, however, the name “ para- 
sitica ” has again reverted to the common Jager, while the other species has 
been usually called “ cepphus ,” after Briinnich. This identification of Briin- 
nich’s name is adopted by Gray, Bonaparte, and other writers. Our reasons 
for rather referring it to the Stercorarius pomarinus will be found under the 
head of the latter. 
Granting, as it is undoubtedly wisest to do, that th % parasitica of Briinnich, 
Linnaeus and Gmelin, is really the common short-tailed Jager, it still remains 
an open question to which species we are to refer the Larus parasiticus of 
Latham. I incline to the opinion that it is based upon the long-tailed spe- 
cies, for the following reason : Although the diagnosis is brief and unsatis- 
1863.] 
