64 DICTIONARY OF BIRDS 
as the highest problem of the systematist, but rather their correct limita- 
tion. Again the arrangement followed in the Pterylographie was of 
course based on pterylographical considerations, and we have its authoyr’s, 
own word for it that he was persuaded that the limitation of natural 
eroups could only be attained by the most assiduous research into the 
species of which they are composed from every point of view. The com- 
bination of these three facts will of itself explain some defects, or even 
retrogressions, observable in Nitzsch’s later systematic work when com- 
pared with that which he had formerly done. On the other hand some 
manifest improvements are introduced, and the abundance of details into 
which he enters in his Pterylographie renders it far more instructive and 
valuable than the older performance. As an abstract of that has already 
been given, it may be sufficient here to point out the chief changes made 
in his newer arrangement. To begin with, the three great sections of 
Aerial, Terrestrial and Aquatic Birds are abolished. The “ Accipitres” 
are divided into two groups, Diurnal and Nocturnal; but the first of these 
divisions is separated into three sections :—(1) the Vultures of the New 
World, (2) those of the Old World and (3) the genus Falco of Linnzeus. 
The “ Passering,” that is to say, the true Passeres, are split into eight 
Families, not wholly with judgment ;! but of their taxonomy more 
is to be said presently. Then a new Order “Picarix” is instituted 
for the reception of the Macrochires, Cuculine, Picine, Psittacine 
and Amphibole of his old arrangement, to which are added three? 
others—Caprimulginx, Todide and Lipoglosse—the last consisting of the 
genera Buceros, Upupa and Alcedo. The association of Alcedo with the 
other two is no doubt a misplaeement, but the alliance of Buceros to 
Upupa, already suggested by Gould and Blyth in 1838 % (Mag. Nat. Hist. 
ser. 2, ll, pp. 422 and 589), though at first sight unnatural, has been 
corroborated by many later systematizers; and taken as a whole the 
establishment of the Picariw was certainly a commendable proceeding. 
For the rest there is only one considerable change, and that forms the’ 
greatest blot on the whole scheme. Instead of the Ratite of Merrem 
being recognized as before as a Subclass, they were now reduced to the 
rank of an Order under the name “ Platysterne,” and placed between the 
“ Gallinacex” and “Grallx,” though it was admitted that in their pterylosis 
they differ from all other Birds, in ways that the author is at great pains 
1 A short essay by Nitzsch on the general structure of the Passerines, written, it is 
said, in 1856, was published in 1862 (Zettschr. Ges. Naturwissensch. xix. pp. 389- 
408). Itis probably to this essay that Burmeister refers in the Pterylographie (p. 
102, note; English translation, p. 72, note) as forming the basis of the article 
“Passerine”’ which he contributed to Ersch and Gruber’s Encyklopédie (sect. iii. 
bd. xiii. pp. 182-144), and published before the Pterylographie. 
* By the numbers’prefixed it would look as if there should be fowr new members 
of this Order; but that seems to be due rather to a slip of the pen or to a printer’s 
error. 
® This association is one of the most remarkable in the whole series of Blyth’s 
remarkable papers on classification in the volume cited above. He states that Gould 
suspected the alliance of these two forms “from external structure and habits alone ;”’ 
otherwise one might suppose that he had obtained an intimation to that effect on one 
of his Continental journeys. Blyth ‘arrived at the same conclusion, however, by a 
different train of investigation,” and this is beyond doubt. 
