1909.] OF THE PASSERINE BIRD ARACHNOTHERA MAGNA, 539 
forms here being examined are from Mexico, South America, 
South Africa, Asia, East India, New Zealand, and Australia, 
or, in other words, very widely separated countries, yet there is 
no mistaking any of the characters of the skeleton of the limbs in 
any of the birds,—they are all distinctly passerine, we might say 
“typically” passerine, had there ever been selected as a reference 
standard a species anywhere, the skeleton of which was to be 
universally considered as the type in this respect for all Passeres. 
It would be interesting to know what species would be selected 
upon a consensus of opinion of ornithotomists everywhere, on 
this point—WMerula perhaps. Typically passerine o1 otherwise, 
however, one would be surprised to note the variations in form in 
some of these bones among these oscine honey-birds, creepers, and 
their kin. ‘To appreciate this to the full extent, the skeleton of 
the limbs of the several species would have to be brought up, 
either in drawings or plastic models, to many times the size 
of the original, and then compared one with another. ‘Take 
the humerus, for example: had we models of this bone from 
all the species in our list each twenty centimetres long, and 
the other proportions correctly reproduced, we should be sur- 
prised at the differences which exist in them, which by this 
means could easily be recognized at a glance, but which other- 
wise must be studied by passing from one to the other with a 
good lens to assist you. 
In Arachnothera magna the humerus has a length of 2°2 ems., 
and its smooth shaft is nearly straight, presenting hardly any of 
the usual sigmoidal curve from whatever point we may view the 
bone. In form it is subcylindrical, being somewhat compressed, 
from its anconal aspect palmad. The radial crest is short and net 
very prominent, while the ulnar tuberosity is conspicuous, and 
the pnewmatic fossa surrounded by a distinct raised margin, which 
between this concavity and the head of the bone on the anconal 
side is raised into a thin and projecting process. What is most 
peculiar is that the head of the humerus is hollow and the 
entrance to the concavity is seen on the anconal side, next to the 
pneumatic fossa, being separated from it by the aforesaid thin 
projecting process. A few small, scattered, pneumatic foramina 
are found at the bottom of the fossa, where they usually occur. 
At the distal end of the bone we find the oblique and ulnar 
tubercles much produced with the olecranon fossa circumscribed 
and well marked. It is confined to the ulnar side of the shaft. 
The ecte- and entepicondylar processes are both distinct though 
not large apophyses. In all these birds there is to be found a /ree 
sesamoid at the elbow-joint. 
Arachnothera longirostris has a humerus resembling the bone in 
A. magna, but in it the caput humeri is not hollowed out in the 
manner described above. In both species there is a distinct and 
circumscribed pit at the distal end of the shaft on the palmar 
surface right next to the ulnar tuberosity. This humerus has a 
