364 
DR. R. W. SHUFELDT’S MORPHOLOGICAL 
parisons of these parts as the}' occur in Micropus and Tacliy- 
cineta , and further ou, when we come to examine the skeleton of 
Chcetura, a few more words on the subject may he added. 
Of the Skeleton of the Limbs in Swallows. — All of the Hirun- 
dinidae agree with the true Passeres in having the little ossicle 
known as the os humero-scapulare at the shoulder-joint, but I 
have failed to find it in the Cypseline birds. 
In the Proc. Zool. Soc. for April 1887 I figured the humerus of 
Tachycineta thalassina, and further on in this article I shall have 
to refer to that drawing. Now, so far as the humeri of the other 
Swallows are concerned, they all more or less resemble the bone 
as found in Tachycineta : they are invariably non-pneumatic, 
proportionately short in the shaft as compared with the size of 
the bird, and quite so relatively when taken in comparison with 
the Passeres generally. Especially in Chelidon is this brevity of 
the humeral shaft noticeable ; and it becomes of interest to know 
that in a specimen of this Swallow I find a humerus 15 millim. 
long to an ulna 24 millim. long, and in Progne a humerus 
22 millim. long to an ulna of 33 millim., while in a Swift 
{Micropus) we have a humerus 11 millim. long to an ulna of 
but 16 millim. in length, showing a difference of 9, 11, and 
5 millimetres respectively. 
Swallows have at least one good-sized sesamoid at the elbow, 
but I thus far have failed to detect any such small bone in a 
Swift; in Micropus , however, I find in the same tendon a small 
nodule of dense cartilage. 
The shafts of both ulna and radius are noticeably straight for 
nearly their entire lengths, and in their general conformation 
depart but little from the usual form assumed by these bones in 
the Passeres at large. 
I have already pointed out elsewhere that n a Swift ( Micro- 
pus ) these bones are also markedly straight, and are, com- 
paratively speaking, almost as short for a bird of its size as is the 
humerus, — Swifts, as a rule, deriving their length of wing from 
the long bones of the pinion, and not from those of the brachium 
and antibrachium. 
Radial and ulnar ossicles are found in the carpus of all 
Hirundine birds, as usual, and iu their form and method of articu- 
lation no departure whatever is made from the composition of 
the wrist-joint, as seen iu all others of the group. 
There are no claws on the finger-end in the manus and 
