195 



European species (P. tridactylus L.). The latter has two well-marked 

 climatic races a large, very light colored northern one (var. crisso- 

 leucus Brandt) and a smaller, darker southern one (var. tridactylus L.). 

 The former has the back white longitudinally, somewhat like our var. 

 dorsaliSy but differs very decidedly in other respects. One is hardly 

 justified in saying that " all the species of this genus are unquestion- 

 ably modified derivatives of one circumpolar stock" (see Coues, Key, 

 p. 194) ; and the statement that " the American seem to have become 

 completely differentiated from the Asiatic and European " is equally 

 objectionable. A comparison of dorsalis and Americanus with the 

 Old World forms, shows plainly that the amount of differentiation 

 scarcely comes up to the qualifications of a difference of race. A 

 comparison of arcticus with the rest also shows that bird to possess 

 every requirement of an independent, and truly distinct species. 



149. SPHYRAPICUSTHYROIDEUS (Cass.). Though this species 

 is not given in Mr. Allen's list, he nevertheless collected it in Colo- 

 rado, but the specimen being in immature plumage was identified as 

 8. nuclialis. 



155. GLAUCIDIUM (PASSERINUM, var. CALIFORNICUM?). 

 Not having seen the specimens of the pygmy owl collected by Mr. 

 Aiken in Colorado, I cannot say positively that they belong to this 

 species. They are quite as likely to be G. ferrugineum, which was 

 collected in Arizona by Lieut. Charles liendire, U. S. A. (See Am. 

 Nat. vi, 370, and Coues' Key, p. 206.) 



178. MELEAGRIS GALLOPAVO. Mr. Aiken has not informed 

 me whether the Colorado bird is var. gallopavo, extending northward 

 along the mountains, or the eastern form (var. sylvestris) reaching 

 westward to the mountains by following the wooded valleys of the 

 rivers across the plains. It is most likely, however, to be the former. 



187. DKMIEGRETTA sp? This is probably the D. Ludoviciana. 

 See ALLEN, Bull. Mus. Comp. Zool., Vol. iii, No. 6, p. 153. 



237. LARUS sp. ? This gull is probably the L. argentatus, var. Cal- 

 ifornicus, which I found breeding very abundantly at Pyramid Lake, 

 Nevada, and less numerously at Great Salt Lake, on Carrington 

 Island. 



It is difficult to see Dr. Coues' reasons for referring this form to 

 Delawarensis, since it has no points at all in common with the. latter 

 species, from which it is perfectly distinct, though clearly referrible 

 to argentatus. 



