88 ORTHOGENETIC EVOLUTION IN PIGEONS. 



near the tip. This white, however, leaves the dark crescentic tip intact. In the 

 phylogenic series I should place Sc. inca as lowest, Sc. squamosa (pi. 36, fig. A) 

 coming next above. 



The genus Geopelia includes 5 Australian species. The 4 species I have studied 

 (G. mauyei, 38 text-fig. 17, seems from descriptions to stand at least below G. striata) 

 may be arranged in the order of their respective stages of development as follows: 



(1) Geopelia tranquilla, with narrow white and black bars running entirely across 

 the front of the neck, with no median interruption. 



(2) Geopelia striata, with bars interrupted in the middle of the neck by a median 

 streak of pale vinous (this species stands lower than tranquilla in having barred 

 feathers along the sides of the abdomen. The two are about equal in rank). 



(3) Geopelia humeralis, with no bars on the front of the neck. 



(4) Geopelia cuneata, with no bars on front of the neck, and bars elsewhere 

 transformed into dots. 



Nos. 1, 2, and 3 all agree in the adult in having the feathers of the wings and 

 back edged by a narrow band of black, giving the whole a squamated or scale-like 

 appearance. 



No. 4 departs most widely (is really of generic rank), and agrees with the earlier 

 members of the series only partially in the juvenile feathers. In the first feathers 

 the bars run across the neck in Geopelia tranquilla, also in G. striata, though not so 

 clearly marked. In G. humeralis the bars are present but not sharp, and are inter- 

 rupted in the median line, so that the Juvenal type corresponds to the adult G. striata. 



Here is a curious series of stages plainly standing in the relation I have indicated. 

 This group of Australian doves furnishes in some respects the best demonstrations 

 of recapitulation that I have thus far (1903) discovered. 



"Temminck says that the black and white bars alternate regularly, and that there is no middle interruption of 

 bars on the neck, breast, or abdomen all of which puts this bird below Geopelia striata. Temminck asserts that 

 G. mangel has only 12 tail-feathers; this would correspond to the number in Scardafella and Gymnopelia. Salvador! 

 (p. 454), however, gives this number as 14, which corresponds with that of other geopelias. 



EXPLANATION OF PLATE 36. 



A. Adult scaled dove, Scardafella squamosa. Toda del., after Knip and Temminck, i, p. 127, pi. LIX, 

 1808-1813. 



This bird should follow S. inca, as it is slightly more differentiated on the wings. "Upper wing-coverts light 

 brown, white towards the tips. Under wing-coverts dark brown edged with black." (See Salvador!, p. 464.) 



The black crescents here very heavy. In inca they are dull. Temminck asserts that this bird has 14 tail-feathers, 

 the 10 central ones of equal length, the 2 lateral ones on each side are strongly " etagfies." Salvadori says the tail- 

 feathers are 12 for both species of Scardafella, and he is undoubtedly right. 



Each feather is edged with a heavy crescentic bar of black, except the under tail-coverts, which are white. The 

 breast and sides have a pinkish (vinous) tinge (similar in .S. inca). Salvadori's phrase, "Young, feathers faintly 

 mottled," recalls strongly the wing of S. inca. 



1-9. Selected feathers from an adult Scardafella inca. Natural size. Toda del., May 1903. 



(Figures 1 to 5 are from right side near wing.) 

 Flo. 1. From lower breast. 



2. From the side, level of wing-bend. 



3. From about middle of wing. 



4. From close to 3. 



5. From the same level, closer to edge of wing. This is the plainest indication of bars, dark and buff alternating. 

 6 to 9. Successive longer under tail-coverts. 



Here again we see the turtle pattern reduced to a thin gray extension of the basal gray. The shaft is dark ; 

 then comes a buff area, and finally the dark edge. 



The dark edge (terminal or subterminal) occurs generally when the dark center is reduced, replaced in part by 

 light e.g., in some common pigeons where red replaces black, etc. 



