352 DR. R. w. shufeldt’s morphological 
the Caprimulgi are nearer the Owls, and only remotely approach 
tbe Trogons. 
Again, I can hardly agree with Mr. Beddard who would retain 
such forms as Antrostomus and Chordeiles in the same “ sub- 
family for surely all the essential structural characters of these 
two forms are oi family and not subfamily rank : a comparison of 
the skulls alone is almost sufficient to determine this point. And 
the breach between Chordeiles and Steatornis must indeed be 
wider than a mere subfamily line can indicate. 
Anatomy of the North- American HiRUNDiNiDiE. 
From my list of material at the beginning of this memoir it 
will be seen that I have at hand specimens of every genus and 
species of Swallow at present entitled to a place in the United- 
States avifauna, and a sufficient series of each to enable me to 
fully investigate their structure. 
I will take them up, species by species, in the order in which 
they occur in the ‘ Check-List ’ of the American Ornithologists’ 
Union, but need not present a synoptical table of their ex- 
ternal characters, for these are well known to ornithologists 
and ornithotomists the world over. 
To commence with them, then, we will take a look at the ptery- 
losis of a specimen of Progne subis, compare it with the figures 
given in my Plate of Ampelis cedrorum, and with Nitzscb’s 
drawing of the pterylosis of Hirundo urbica in his ‘ Pterylo- 
graphy,’ and next with other American Hirundinidce. 
Now it will be remembered that we found the pterylosis of 
Ampelis to agree essentially with most true Passeres, wherein, 
upon the dorsal aspect of the body, the chief feature is that the 
“ spinal tract ” terminates in a lozenge-shaped pteryla situate 
mesially between the thighs ; and on the ventral aspect w ? e have 
another well-known distribution of the pterylse characteristic of 
most Passerine birds. Progne differs from all this, and agrees 
in the main with Hirundo urbica as figured by Nitzsch. 
This author, however, does not present in his work a ventral 
view of the pterylosis of a Sw allow 7 , but says in his text that 
“the single genus Hirundo, wdiieh constitutes this group [Hirun- 
dines ], differs more than any other in its habitus from the 
general type of the Singing-birds, and in this inspect approaches 
* P. Z. S. 18S6, p. 153. 
