134 ^^^' ^' I^o'^^tt. 



but it will be quite easy to discern the limbs, pigment cells, 

 tail appendages, &c., of the mature Zooea though still enclosed 

 in the &gg envelope. 



31. — Species and Varieties in Birds. 



By Henry E. Dresser, F.L.S., F.Z.S., &c. 



Read 12th April, 1882. 



There are doubtless many here present who have, at some 

 period, tried to work out one of the groups of birds, insects, or 

 other animals, and whoever has done this will be fully aware 

 of the extreme difficulty in defining the difference between a 

 species and a simple variety. As I have, during the time I 

 have studied Natural History, devoted my time chiefly to 

 birds, and more especially to those which inhabit the Pal^arctic 

 and Nearctic regions, I propose, in making a few remarks on 

 species and varieties, to refer chiefly to those found in the 

 former region, which will be better known to my audience than 

 those frequenting the Nearctic region. 



Many years ago, even as late as during the last twenty- 

 five years, collectors were satisfied if they possessed a male 

 and female of each species, and the idea of any climatic 

 variation requiring illustration by means of a series of birds of 

 the same species from various localities was not thought of, 

 and if a bird from some distant country, differing but slightly 

 from one of our European species, was obtained, it was 

 generally put down at once as a distinct species. 



One of the first ornithologists to recognise the variability of 

 our common species of birds was the celebrated German 

 naturalist. Dr. C. L. Brehm, but he at once put down every 

 variation as constituting a specific distinction, and hence 

 burdened the ornithological literature of the day with a vast 

 amount of useless synonymy, to the great discomfort of work- 

 ing ornithologists. Thus he sub-divided the common Treepipit 

 into 13, and the Meadow Pipit or Titlark into eight species, the 

 diff"erences in many cases being so slight that I could not make 

 them out. That birds belonging to the same species differ not 

 a little according to the nature of the soil they frequent or the 

 altitude where they are found, is now very generally conceded ; 

 hence those birds which frequent sandy, dry districts are much 

 paler than others of the same species which live in darker and 

 more fertile soil, but these differences are certainly not specific, 

 but only individual ; but by recognising these varieties as 

 species, Brehm multiplied the number of European birds very 

 greatly, and got European ornithology into a state of chaos, 



