SWIFTS. 



437 



palatines of tlic young, as pointed out liy Parker, who says tliat in the young luini- 

 ming-birds they agri'e in f/oicrul \v\t\i yount; Passeres, "but in partinilar with both 

 young and adult of that family (if liinls which has most similarity to them in genei-al 

 bodily structure, namely, swifts." 



In view of the extreme external ' isomorphism' of the swifts and the swallows, 

 and the remarkable tenacity with which ornithologists have stuck to arrangements 

 based cliiefly upon the external appearance, the comparatively early recognition 

 of their being totally different on account of their internal structure would be sotne- 

 what surprising but for the fact that there are also a number of easy external charac- 

 ters by which they are at once sejjarated. The swifts, or Mickoi'odidvE, and the swal- 

 lows are, indeed, " only ' second cousins,' and more alike 

 in their habits and mode of dress than in their real nature," 

 as will be ap])arent by the following juxtaj)osition of their 

 differences. Externally they may be easily distinguished ; 

 the swifts by having ten jirimaries, not more than seven 

 secondaries, and only ten tail-feathers, while the swallows 

 have but nine primaries, at least nine secondaries, and 

 twelve tail-feathers. The swifts have also the dorsal tract 

 bifurcate between the shoulders, while in the swallows it 

 is simple. Internally they differ in a great number of 



points, but we shall only mention that the swifts have a ^^^. ,,,;,._ „i„g,^,„ <,f „„. ^iiw- 

 pointed manubrial iirocoss and no posterior notches to the ""'scies in a imniminij-ijini a-nta- 



l I- ^ f/ona f/zr/rr.';); imiscles with loilgltuui- 



sternum, while the swallows have the manubrium bifur- niiiteiuions witu transvers.^ lines; 



' emrl, exti'iisor metacarpi rauialis 



catc, and the posterior border deeply two-notched; the ihikus ; a, huinerus ; «>•, secumiary 



* ' *^ rcniiges : t, triceps ; fpb^ tensor 



former have a mvological formula A-t-, the latter AXY-r-; patagii brevis ; ipi, tensor patagii 



^ 1 • 1 longiis. 



the former arc synjielmous, the latter are schizopelmous ; 



the former have a i)eculiar arrangement of the tensor jiatagii brevis, the latter have 

 the general arrangement of the Passeres, to be explained in the introduction to that 

 order; the former have a simjile syrinx without intrinsic muscles, the latter have a 

 very specialized syrinx ; the former are without ca;ca, the swallows possess them, etc., 

 the total effect being that the swifts are Picarians, and the swallows are Passeres. 



The swifts are found all over the globe, except in the extreme cold regions and in 

 New Zealand, being most abundant in the tropics of America and the Oriental region, 

 considerably over fifty species being known altogetlu'r. The peculiar structure of the 

 feet furnishes excellent characters for subdividing the family in two minor groujis or 

 sub-families, the Micropo<lina3 and the Cha-turime. The latter have the feet nor- 

 mally constructed w'ith the usual number of ph.alanges, viz., 2, 3, 4 and 5, while the 

 true swifts have the number of phalanges of the third and fourth toes reduced to 

 three, the formula, consequently, being 2, 3, 3, 3. At the same time the first toe is 

 directed more or less forwards or inwards ; in other words, the true swifts are iiamjiro- 

 dactylous. Another feature is that their tarsi are feathered, while the Chieturinaj have 

 them })are. 



Kegarding the Chaturime as the more generalized type, we are at once confronted 

 with the ]>retty tree-swifts {JJendrocheliduti) from India and the Malay Archipelago, 

 wliich are provided with a feather-crest on the head, and very lengthened outer tail- 

 feathers. In the same regions, and also in many of the Polynesian islands (one S]iecic3 

 even in Madagascar), are fo\m<l the ]iigmies of the family, the so-called swiftlets ( ('ol- 

 localia), inconspicuous looking, dusky-colored birds, but famous as the manufacturers 



