V °g 1- X l Recent Literature. IQ? 



of two colors the pigments are apt to get confused as to which is their 

 proper route, and hence both come upon the same feather [in 'hybrid' 

 feathers] by accident, as it were." Is it possible that Mr. Keeler is un- 

 aware that the tip of the feather forms first, and receives its pigment and 

 markings, whatever they may be, before the middle and lower parts of the 

 feather have passed beyond the gelatinous stage of the as yet not fully 

 developed feather? This being the case it is needless to discuss "lines of 

 least resistance" and "the development of pigment in mass when an 

 obstacle is encountered," as illustrated by our author in the unhappy 

 simile of a "panic-stricken mob"! Neither is it necessary to consider the 

 various classifications and generalizations based on this erroneous depart- 

 ure, 1 that fill so many of the subsequent pages. Alas, the fewer facts for 

 a nicely spun theory the better! 



At page 181 he gives a list of markings not known to him to occur 

 among birds; but if he had broadened his survey to other regions of the 

 world he would have had no trouble in finding nearly all of them. Even 

 our own Woodcock would have given him an example of "the top of the 

 head barred," while numerous species of Old World Cuckoos and King- 

 fishers would have furnished still finer illustrations. And so on with 

 most of the other unknown markings. 



As one example, out of many, of slipshod generalization take the fol- 

 lowing from p. 196: "I would suggest that there is great probability that 

 the habits of birds have been more or less determined by their colors" ; as 

 for example, in a group of olive green or gray birds "those which formed 

 the habit of living in trees would survive, while those frequenting the 

 ground, being more conspicuous, would perish," as would in like manner 

 "brown birds which got up among trees" instead of remaining on the 

 ground! The very next bird mentioned (p. 197) is the Brown Creeper, 

 which has developed a "special protective resemblance" to the bark of 

 trees. 



1 Even the most rudimentary knowledge of the method of feather growth, such for 

 instance as could be gained from Burmeister's note on the subject in Nitzsch's 'Pteryl- 

 ographie,' would have saved our author this humiliating mistake. Also if his gen- 

 eral knowledge of feather structure had been a little more extended he would have 

 saved himself the trouble of describing as 'A Supposed New Feather Structure' (Zoe, 

 III, Oct. 1892, p. 257), the simple th'read-like form of feather known since the time of 

 Nitzsch as the filopluma, and mentioned in so readijy accessible a work as Coues's 

 'Key to North American Birds' (p. 186). These filoplumes are present probably in 

 all birds, and over large portions of the feathered tracts, instead of possibly proving, 

 as Mr. Keeler suggests, "to be a generic character" in our Orioles. An inspection of 

 plucked fowls in markets will furnish an instructive illustration of the general charac- 

 ter of filoplumes, for which Mr. Keeler has so recently proposed the name Pseudopi- 

 lum. In this connection we will venture to suggest that had our author devoted 

 some time to a general study of pterylas in connection with special color areas he 

 would have been rewarded by the discovery of many suggestive coincidences, and 

 also that use of the microscope would have thrown much light upon the general sub- 

 ject of feather structure in its relation to coloration. 



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