Recent Literature. 1 69 



and to be subordinated in rank by a trinomial appellation." In a foot- 

 note the author adds : "It should not be inferred from our remarks in this 

 connection that we find the use of trinomials inconvenient in practical 

 application. On the contrary, no other method seems at all adequate to 

 the proper discrimination between isolated and intergrading forms, and 

 the difficulty in the cases above alluded to arises wholly from the want of 

 sufficient material to decide the question of intergradation or the contrary." 

 In regard to the treatment of doubtful cases " the greatest care has been 

 taken," and " previous conclusions" have been "carefully reconsidered, 

 with the aid of all the material accessible, including many specimens not 

 previously in hand. This reconsideration of the subject has, in not a 

 few cases, resulted in a reversal of former opinion, specimens from impor- 

 tant localities not before represented often deciding the point one way or 

 the other. Every form whose characteristics bear unmistakably the 

 impress of climatic or local influences, gradually less marked toward the 

 habitat of another form, with which it thus intergrades, and all forms 

 which certainly intergrade, no matter how widely distinct the opposite 

 extremes may appear (e. £■., Colaptes auratus, and C. mexi'canus, and 

 the different races of Passerella), together with intergrading forms whose 

 peculiarities are not explained by any known 'law' of variation, have 

 been reduced to subspecific rank. On the other hand, where the difference 

 between allied forms is slight, but at the same time apparently constant, 

 and not necessarily coincident with a difference of habitat (e.g., certain 

 small Thrushes and the various forms of Junco), specific rank is upheld. 

 There are some forms which future investigation, based upon adequate 

 material may decide to be of different rank from that accorded them 

 here. We cheerfully acknowledge our fallibility, but at the same time 

 would say that we have endeavored to be as consistent as possible, giving 

 the rank of each form as it appears in the light of our present knowledge, 

 independent of previous conclusions" (op. ciL, pp. 9, 10). That the 

 revision here presented is impartially and conscientiously made there 

 can be no doubt, e.vidence of which is afforded by the cancelling of 4 

 species and 6 varieties for the erection of which Mr. Ridgway is himself 

 either wholly or in part responsible, while others for which Professor 

 Baird stands sponsor share a similar fate. The really few changes in 

 this respect from the status in Baird, Brewer, and Ridgwav's " History 

 of North American Birds " and Coues's " Check List " augurs well for a 

 reasonable degree of fixity so far as forms now recognized are concerned. 

 As already indicated, nomenclatural changes, simply as such, are nu- 

 merous, affecting many generic as well as specific names. Very few of 

 them are, however, now for the first time introduced; quite a proportion 

 have gradually gained currency during the last five years, but many of 

 them date from April, 1SS0.* While quite a number of the long-familiar 



* See Coues, " Notes and Queries concerning the Nomenclature of North American 

 Birds," Bull. Nutt. Orn. Club, V, pp. 95-102, April, 1880. Ridgway, " Revisions of No- 

 menclature of certain North American Birds," Proc. U. S. Nat. Mus., 1880, pp. 1-16, 

 " March 27, 1880." 



