62 Recent Literature. [January 



the birds of that very interesting region, which embraces the so-called 

 'Russian Lapland.' Very properly, however, the author has ignored 

 the political borders and includes part of Norwegian East-Finmark west to 

 the Tana-fjord and Tana-elv. Towards the north and east the region is 

 bordered by the Arctic Ocean and the White Sea. 



The work, in the first place, is intended to be a report on the author's 

 own explorations in that region during the summer of 1S80, but ornitholo- 

 gists will be thankful that he intended it to include the observations of 

 his many predecessors, for he has succeeded in producing a very valuable 

 faunistic monograph of one of the most interesting parts of the Palsearctic 

 Region. It will be seen, from the map. that the province in question 

 connects the Scandinavian Peninsula with the Eurasian Continent. Scan- 

 dinavia during the Glacial Period was probably uninhabited by any birds 

 except, perhaps, the most Arctic species, covered, as it was. with enormous 

 glaciers, and separated from the rest of the Western Palaearctic Region 

 bv a wide sea covering the German and Russian lowlands and uniting the 

 Arctic and the Atlantic Oceans to the east of the peninsula. When the 

 ice receded and the land rose, an immigration of animal life commenced 

 from two different directions— from the south over the Danish Islands, and 

 from the east over Finland, the broad neck of land which now separates 

 the Baltic and the White Sea. This is not only a hypothesis invented to 

 explain the constitution of the present fauna, but it is an observed fact, for 

 the immigration both ways continues to-day, and the regular additions 

 to the Scandinavian fauna during this century can be distinctly and posi- 

 tively traced. Thus it happens that a Central European, a Siberian, and 

 a truly Arctic avifauna meet just in the region which Mr. Pleske has 

 chosen for his monograph. The complexity of the migrating routes which 

 pass along or cross this same section is well shown on the map accompa- 

 nying Palmen's 'Zugstrassen der Vogel,' giving additional interest to the 

 region, and explaining the fact that the author treats of over 200 species of 

 birds, notwithstanding that the chief part of the country included is sit- 

 uated to the north of the Arctic Circle. 



Mr. Pleske has had one great disadvantage : he has not had the opportu- 

 nity of verifying his predecessors" statements and identifications by exam- 

 ining their specimens. In fact, most of the older records and many of 

 the recent ones are not at all based on specimens, and those which have 

 been collected are scattered all over the world. In many cases, therefore, 

 there is a lack of absolute identification, which is felt more especially in 

 the case of species, the subspecies or nearest allies of which, are very 

 difficult to discriminate. Thus we are ignorant of the true status of 'JPicus 

 minor and of 'Pica rustica' from that region, whether they are the Cen- 

 tral European forms, or the Siberian subspecies, or both, or intermediate 

 ones between the two. On the other hand, it is evident that the author, 

 when having access to specimens, knows how to discriminate. Thus we 

 note with satisfaction that for the first time in a work of that scope the 

 Redpolls (Acanthis) are correctly understood, for Mr. Pleske clearly dis- 

 tinguishes, discusses, and describes three forms as occurring in the region, 

 viz: A. linaria, A. holbcclli, and A. exilipes. 



