NATURAL SCIENCES OE PHILADELPHIA. 



189 



Name. 



Pelidna Americana. 



Pelidna alpina. 



("Schinzii,"). 



Length. Extent. Wing. Bill. Tarsus 



8-50* 

 9-00* 

 8-25* 

 7-90f 

 8-1 Of 

 8-40f 



15-40* 

 14-00* 



4-70 

 5-05 

 4-65 

 4.25 

 4-70 

 4-50 



1-50 

 1-74 

 1-54 

 1-40 

 1-42 

 1-40 



1-08 

 1-13 

 1-03 



90 

 1-02 



92 



Toe. 



98 



1-05 



95 



90 



88 



85 



* Fresh; on authority of collector, t Of skin; approximate only. 



The comparative diagnoses would be briefly as follows: 



P. alpina. Length 8 inches. Bill, average, 1-4. Tarsus but little if any 

 longer than middle toe. Length of tarsus and toe 1-75. 



P.Americana. Larger; length 8-5 inches. Bill average 1-7 ; disproportion- 

 ately longer, stouter, more decurved. Tarsus decidedly longer than the middle 

 toe ; legs considerably longer; length of tarsus and toe 2 inches. 



Among the specimens from the west coast there appear to be two very de- 

 cided types. One is that common to the Atlantic coast, in which the bill mea- 

 sures on an average 1'50 of an inch in length, and the wing 460. Of the other 

 there are three specimens before me, collected at different times, absolutely 

 identical in size and proportions, and differing greatly both from eastern speci- 

 mens and all others from the west coast. In these the bill measures 1-72 of an 

 inch, being nearly a fourth of an inch longer than in P. Americana ; the wing 

 is nearly five inches ; the legs are somewhat longer, and the whole bird con- 

 siderably larger. The differences, indeed, between these specimens and the 

 average of P. Americana are nearly if not quite as great as those which separate 

 that latter species from the alpina. These facts are of importance, and would 

 seem to point to one of the following considerations : either the three specimens 

 alluded to belong to a species distinct from the Americana, or that they repre- 

 sent one extreme, and P. alpina, or more properly T. Schinzii, Brehm.,* the 

 other of one and the same species, of which P. Americana is the intermediate 

 form. I cannot but think, however, that the former supposition is the most 

 probable; for it seems almost impossible in one species there should be such 

 variations, and those too of such a radical nature as are presented by specimens 

 of Pelidna from different localities. Thus, to consider a bird in which the bill 

 measures 120, the leg 1-75, and the wing 4-40, (as in the smallest specimen of 

 Pelidna before me,) as specifically identical with one in which these parts were 

 respectively 175, 2-10 and 4-95, would be almost without a parallel in orni- 

 thology ; while, at the same time, if they be considered distinct, it is impossible 

 to avoid recognizing al?o the intermediate form. But if, as I think has been 

 pretty conclusively shown, the American bird is distinct from the European, 

 then the west coast specimens above referred to are equally worthy of specific 

 distinction.! Still, with but three specimens before me, I do not venture, in 

 the case of so variable a bird as a Sandpiper, to present it as distinct; but 

 should the above differences be found constant, and showing no graduation 

 towards the Americana, I should have no hesitation in so doing. In the event 

 of their proving really distinct. I would propose the name of Pacifica as an ap- 

 propriate one. 



* With but a single specimen of Tringa Schinzii before me, I am not prepared to ex- 

 press any opinion with relerence to its relationships to Pelidna alpina. In this paper I 

 consider it as merely a smaller race of the latter, entirely upon the high authority of the 

 General Report. 



t In the field notes of the late Dr. C. B. R. Kennerly, I find the opinion expressed that 

 they arc distinct; and I am informed by Dr. Geo. Suckley, U. S. \., that he has always 

 doubted the specific identity of the various specimens of Pelidna from the west coast. 

 Both of these gentlemen have enjoyed excellent opportunities for observation and com- 

 parison, and their opinions should carry with them considerable weight. 



1861.] 



