1896.] ANATOMY OF THE HOATZIN, 625 
lost in the tendon over the knee, through which, in the normal 
condition, it passes. I dissected carefully for the ambiens in each 
leg of two of my specimens. In one case the ambiens was 
completely absent above the knee, and there was no trace of its 
tendon in the fascie and tendon over the knee. But in each of 
these legs(as shown in fig. 4, p. 626)a strong round ligament left the 
fibula, in the position in which the ambiens tendon of a bird with 
a normal ambiens crosses the fibula. This tendon passed down 
and sent a branch to each of the three perforated flewors of the 
Fig. 3. 
BSART. yastus ai at 
hy 
3\-I. “i 
‘FLEX. COM. 
Thigh-muscles of Opisthocomus cristatus ; posterior view. 
Sart., Sartorius. Vast.int., Vastus internus. Addue., Adductors. Semitend., 
Semitendinosus. Semimem., Semimembranosus.  4G.t., Gastrocnemius, 
tibial head. G.m., Gastrocnemius, middle head. G-.e., Gastrocnemius. 
external head. So/., Soleus. Flex.com., Flexor communis digitorum, 
I. Flexor longus hallucis. 
digits. In a second specimen I found the ambiens above the 
knee. The tendon was lost at the knee-joint, but a rudiment 
slightly different from that in the first case was present in each 
leg below the knee. From the fibula, immediately distal to the 
attachment of the biceps tendon, three fibrous slips passed 
respectively to the perforated flexor muscle for the second, third, 
and fourth digits. It is well known that Garrod regarded the 
