STUDIES OF THE HACKOCHERES. 
355 
is pretty well known, it will not be necessary for me to enlarge 
further upon my account of it. 
But the principal thing to he borne in mind in the present 
connection is, that Swallows, Swifts, and Humming-birds all 
depart from the more typical pattern of pterylosis found in 
true Passeres. And in the case of the Swallows and Swifts, so 
far as Xitzsch’s figures and descriptions go, for I have not yet 
examined the Cypseli myself for this character, the pterylosis of 
the latter is of such a pattern that it requires hut very little 
modification to make it agree with the pterylosis of a Swallow. 
Indeed, in those Swallows where the “ saddle-pteryla ” of the 
dorsum joins its bifurcations with the anterier end of the “ rump- 
hand,” the pattern is nearly the same, differing principally in 
relation, width of the tracts, and position of the bifurcation of 
the saddle, which, in Cypselus aims, is between the shoulders. 
On the Mode of Insertion of the Patagial Muscles 
in the Swalloivs. 
Scarcely any difference is apparent among the various species 
of Swallows at hand in regard to the mode of insertion of 
this group of patagial muscles, now known to he of so important 
a character in the taxonomy of the class. I have carefully ex- 
amined them in all the American species, and find that, so 
far as the tensor patagii brevis is concerned, both its origin and 
insertion seem to he almost typically Passerine. This observa- 
tion applies with equal truth to the tensor patagii longus ; and as 
these muscles are now so well known to all working morpholo- 
gists, I need not redescrihe them here ; moreover, in figure 2 
of Plate XVII., I have drawn them for Ampelis, which will 
recall their appearance for the Passeres. 
During the course of my dissections upon this region in the 
Hirundinidce, however, I came across, as I did in Ampelis, what 
I am inclined to believe is a hitherto undescribed muscle, at 
least so far as Grarrod’s descriptions go. It first came to my 
notice in a specimen of Progne subis, whereupon I at once dis- 
sected a number of other individuals of the same species, and 
found it equally well developed in all of them. 
This muscle, in part, is a dermal muscle, and arises from the 
integuments on the anterior aspect of the neck at about its lower 
