344 
DR. R. W. SHUDELDt’S MORPHOLOGICAL 
in alcohol. It will be observed that the brain of Chordeiles 
is considerably larger than tbe brain of the Whip-poor-will, 
notwithstanding the fact that in the latter bird the skull is 
markedly wider, longer, and flatter; while iu the Nigh thaw k tbe 
parietal region of the skull is more dome-like and rounded. 
The eyes in the Nighthawk are rather larger than they are 
in the Whip-poor-will ; while in the latter the recurved limbs of 
the hyoidean cornua are longer, more median, and reach higher 
up on the cranium than they do in Chordeiles. 
Marked differences of course characterize the skulls of these 
two forms ; but of this we shall have something to say later : the 
inter-ramal layer of muscles is thicker in Chordeiles than it 
is in Antrostomus, completely shutting out of sight the hyoidean 
apparatus in the former bird, while its form can be easily made 
out in the last-named type through this muscular layer. 
We need not enter here upon a comparison of the structure of 
the neck in these two birds, but proceed at once to remove 
the skin from the body and limbs. 
On the Mode of Insertion of the Patagial Muscles of the 
Pectoral Limb. 
These I not only examined in the specimens before me of An- 
trostomus and Chordeiles texensis, but in a number of other 
species of the latter genus, with the following results. Our 
American Whip-poor-will, I find, has the tendons of these 
patagial muscles of the arm inserted in precisely the same 
manner as Grarrod found them iu Caprimulgus europceus, see 
either in his “ Collected Memoirs,” or in my copy of his figure 
in my “ Contributions to the Anatomy of Geococcyx ” (P. Z. S. 
1886, p. 471). But it will be as well to mention here that 
these tendons are far more slender than one would be led to suppose 
from this anatomist’s drawing alone. They are exceedingly 
delicate in structure. This remark, however, does not so well 
apply to these tendons of the patagial muscles as we find them 
in the genus Chordeiles ; here they are decidedly broader and 
stronger than they are in the Whip-poor-will, and also present 
certain well-marked differences. Now, although the plan of 
arrangement is essentially the same in the Nighthawks, we find 
that the tendon (the main tendon) of the tensor patagii brevis is 
