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 fascias and tendon over the knee. But in each of 

 these ]egs(as shown in fig. 4, p. G26)a strong round ligament left the 

 fibula, in the position iu 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 jlexors of the 



rig. 3. 



SEMI-TEND. 

 -SfMf-MEM. 



FLCX. COM. 

 Thigh-muBcles of Opisthocomus cristatus ; posterior view. 



Sart., Sartorius. Vast.int., Vastus intemus. Adduc, Adductors. Semitend., 

 Seraitendinosug. Semimem., Semimembranosus. G.t., Gastrocnemius, 

 tibial head. G.ot.,, Gastrocnemius, middle bead. G.e., Gastrocnemius, 

 external head. Sol., Soleus. Flex.com., Flexor communis digitorum, 

 I. Flexor longns 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 



