366 
DR. R. W. SnUFELDT’s MORPHOLOGICAL 
present drawings of the same here to illustrate my meaning. 
A glance at the contour of Micropus will be sufficient to con- 
vince us that in general outline it is strikingly, indeed actually, 
far more like any one of our Swallows, as P rogue for instance. 
And, apart from the resemblance which its short antibrachium 
gives it to Trocliilus (PI. XXIV. fig. 39), it has no other character 
upon this aspect of its body to support the view that any true 
relationship exists between it and the latter bird. For the 
rest, to my mind, shortness of the antibrachium amounts to 
nothing as an indication of affinity unless correlated with actual 
similarity of form in its details. Chcctura having a deeper 
Carina to its sternum than has the other Swift, Micropus , it bears 
a somewhat more general resemblance to the body of a Humming- 
bird (fig. 39) than it otherwise would do, or as does Micropus ; 
but some of the smaller Petrels might hold an equal claim to 
affinity with Trocliilus were it based upon such data as this. 
Coming to a few of the true characters, we find the bill, the 
position of the commissure of the gape, the feet, and some other 
points widely different in a Swift from what the corresponding 
characters are in a Humming-bird ; and when Micropus is the 
Swift chosen for the comparison, the entire contour of its body 
differs from that of Trocliilus in all important particulars. 
Let us next examine the pterylography of these three birds, 
and see what it indicates in regard to their affinity. 
Nitzsch has presented us with fairly good figures of the 
pterylography of Cypselus apus and Trocliilus moschitus (Pterylog., 
ed. Sclater, pi. iii. figs. 16-19) ; but there are several points 
requiring elaboration in his account, while in other particulars 
his comparisons are deficient. 
Taking his figures and descriptions just as they stand, how- 
ever, and bringing into the discussion his figure 14 on the same 
plate, of Jlirundo urbica, we find that the pteryloses of the Swift 
and Swallow, so far as their heads are concerned, agree, with the 
exception that the Swift possesses those peculiar crescent-shaped 
apteria, one over each eye ; these are absent both in the Swallow 
and Humming-bird. 
But the Humming-birds have a median naked space of a 
spindle-shaped outline on the crown, situated longitudinally, and 
between the eyes and the base of the superior mandible. This 
is well marked in all species which I have thus far examined, 
and it was overlooked by Nitzsch ; moreover, it is absent in 
the Swifts and Swallows. 
