WZ Lucas, the Main Divisions of the Swifts. [January 
‘tarsus’ is much shorter and wider in Dexdrochelidon than 
in any of its relatives, and the anterior and posterior surfaces in- 
stead of being deeply grooved for the reception of tendons are 
decidedly convex. The first metatarsal is well developed and is 
placed well up on the ‘tarsus,’ the ungual phalanges are not of 
the regular Cypseline pattern, and the phalanges, within the 
penultimate, instead of being short or obsolete are moderately 
long. Finally the ‘tarsus’ is shorter than even the first digit, 
while in all other Swifts it is longer, notably so in Chetura. 
From the preceding notes it may be seen that marked differences 
separate the genus Denxdrochelidon from the other Swifts, while 
in some points it seems to incline towards the Goatsuckers. Some 
of the distinctions existing between Dexdrochelidon and the other 
Swifts are merely differences of degree, but others are differences 
of kind, so that Denxdrochelidon not only differs from its rela- 
tives, but possesses structural characters of its own that appear 
quite equal to those of the rest of the Swifts combined. These 
differential characters are greater than those existing between the 
Thrushes and the Wrens, or even, I should say, between the 
Crows and the Swallows, so that although the material at hand 
is small, it is quite sufficient to warrant the formation of a new 
family for the members of the genus Dendrochelidon. The 
name proposed for this family is Dezdrochelidonide. 
The precise status of the Swifts may well be called a little un- 
certain, although the tendency certainly is to consider them as an 
order. Mr. Gill’s term of super-family has been applied to the 
Swifts by Mr. L. Stejneger and may safely be used. Osteologi- 
cally the group may be diagnosed as follows. 
Super-family MrcRopoDOIDEA. 
Palate zgithognathous ; maxillo-palatines unciform ; manubrium 
rudimentary; xiphoid margin of sternum entire, costal process 
small; coracoid short, not implanted in a groove, epi-coracoid 
feebly developed; furcula widely U-shaped, hypoclidium small, 
epiclidium obsolete. 
The two families into which this super-family is divided may 
be differentiated as follows. 
