1907-8.] An Account of a Brachydactylous Family. 45 
order to obliterate the crease between it and the bases of the toes. The toes 
are almost square in shape. 
Facts revealed by Radiography. — The X-rays show that the middle 
phalanx is not really absent. In Nos. 43, 50, and 110 (fig. 8) it is true 
that only two bones are visible in each finger. As No. 43 was one of the 
first cases examined, I was inclined to agree with Farabee that each digit 
contains only two phalanges, the first and the third, and that the second 
one was absent. It is, however, readily seen in these same figures that the 
terminal phalanx differs in shape from the normal phalanx. This difference 
is clearly manifest on comparing the radiographs of normal and abnormal 
hands with one another. 
In Nos. 45, 56, 88, 90, 94, 95, 96, and 98 the middle phalanx is visible 
as a separate bone in the middle finger. Here it has a cubical shape 
corresponding precisely with the base of the terminal phalanx in each of 
the other fingers. 
This cubical basal portion is the second (middle) phalanx that has 
become ankylosed to the terminal phalanx, which normally is triangular 
or pyramidal in shape. The pyramidal distal portion of these bones 
corresponds to the ungual phalanx and the basal cubical portion to the 
middle phalanx. 
The middle phalanx is, in a few instances, separate in two fingers (the 
middle and ring) in Nos. 94, 96, 98, 101. It does not exist as a separate 
bone in either the index or little finger in a single adult. 
What has happened to the middle phalanx ? It varies in two respects 
from the normal : — 
(1) It is very short. 
(2) It generally becomes ankylosed to the base of the terminal phalanx. 
In several individuals a distinct but functionally useless joint can be 
felt next the terminal phalanx in the middle finger, and less often in the 
ring finger. The fact that the middle phalanx is abortive but not com- 
pletely absent is proved conclusively by an examination of Nos. Ill (fig. 8) 
and 156, which are those of young children, and in which the middle phalanx 
is seen before ankylosis has occurred. 
The epiphyses at the bases of the phalanges are ossified from separate 
centres, but the discs shown in these figures at the bases of the phalanges 
are not epiphyses, but are the rudimentary second phalanges. 
It is thus clear that there is no real absence of the second phalanx in any 
individual, but merely a rudimentary condition, and that at a certain 
stage of development there is a union of this with the terminal phalanx. 
The essential feature of the abnormality apparently consists in an 
